CINXE.COM

<!DOCTYPE html> <html lang="en" dir="ltr" prefix="og: https://ogp.me/ns#" class="no-js"> <head><script type="text/javascript" src="/_static/js/bundle-playback.js?v=HxkREWBo" charset="utf-8"></script> <script type="text/javascript" src="/_static/js/wombat.js?v=txqj7nKC" charset="utf-8"></script> <script>window.RufflePlayer=window.RufflePlayer||{};window.RufflePlayer.config={"autoplay":"on","unmuteOverlay":"hidden"};</script> <script type="text/javascript" src="/_static/js/ruffle/ruffle.js"></script> <script type="text/javascript"> __wm.init("https://web.archive.org/web"); __wm.wombat("https://www.epa.gov/uic/class-ii-oil-and-gas-related-injection-wells","20211028015312","https://web.archive.org/","web","/_static/", "1635385992"); </script> <link rel="stylesheet" type="text/css" href="/_static/css/banner-styles.css?v=S1zqJCYt" /> <link rel="stylesheet" type="text/css" href="/_static/css/iconochive.css?v=3PDvdIFv" />  <meta charset="utf-8"/> <link rel="canonical" href="https://web.archive.org/web/20211028015312/https://www.epa.gov/uic/class-ii-oil-and-gas-related-injection-wells"/> <link rel="shortlink" href="https://web.archive.org/web/20211028015312/https://www.epa.gov/node/78919"/> <meta name="description" content="This page provides background information on the uses of Class II wells, their regulatory requirements, and how the requirements protect USDWs."/> <meta property="DC.title" content="Class II Oil and Gas Related Injection Wells"/> <meta property="DC.description" content="This page provides background information on the uses of Class II wells, their regulatory requirements, and how the requirements protect USDWs."/> <meta property="DC.Subject.epachannel" content="Learn the Issues"/> <meta property="DC.type" content="Overviews and Factsheets"/> <meta property="DC.date.created" content="2015-03-27"/> <meta property="DC.date.modified" content="2021-09-14"/> <meta property="DC.date.reviewed" content="2022-09-14"/> <meta property="DC.creator" content="US EPA,OW"/> <meta property="DC.language" content="en"/> <meta property="WebArea" content="Protecting Underground Sources of Drinking Water from Underground Injection (UIC)"/> <meta property="ContentType" content="Basic page"/> <meta property="og:site_name" content="US EPA"/> <meta property="og:type" content="website"/> <meta property="og:url" content="https://web.archive.org/web/20211028015312/https://www.epa.gov/uic/class-ii-oil-and-gas-related-injection-wells"/> <meta property="og:title" content="Class II Oil and Gas Related Injection Wells | US EPA"/> <meta property="og:description" content="This page provides background information on the uses of Class II wells, their regulatory requirements, and how the requirements protect USDWs."/> <meta property="og:image" content="https://web.archive.org/web/20211028015312im_/https://www.epa.gov/sites/all/themes/epa/img/epa-standard-og.jpg"/> <meta property="og:image:width" content="1200"/> <meta property="og:image:height" content="630"/> <meta property="og:updated_time" content="2021-09-14"/> <meta property="og:image:alt" content="U.S. Environmental Protection Agency"/> <meta property="og:country_name" content="United States of America"/> <meta property="article:published_time" content="2015-03-27T15:37:15-04:00"/> <meta property="article:modified_time" content="2021-09-14"/> <meta name="twitter:card" content="summary_large_image"/> <meta name="twitter:image:alt" content="U.S. Environmental Protection Agency"/> <meta name="twitter:image:height" content="600"/> <meta name="twitter:image:width" content="1200"/> <meta name="twitter:image" content="https://web.archive.org/web/20211028015312im_/https://www.epa.gov/sites/all/themes/epa/img/epa-standard-twitter.jpg"/> <meta name="MobileOptimized" content="width"/> <meta name="HandheldFriendly" content="true"/> <meta name="viewport" content="width=device-width, initial-scale=1.0"/> <meta http-equiv="x-ua-compatible" content="ie=edge"/><script type="text/javascript">(window.NREUM||(NREUM={})).init={ajax:{deny_list:["bam.nr-data.net"]}};(window.NREUM||(NREUM={})).loader_config={licenseKey:"ead36e43ac",applicationID:"529886857"};window.NREUM||(NREUM={}),__nr_require=function(t,e,n){function r(n){if(!e[n]){var i=e[n]={exports:{}};t[n][0].call(i.exports,function(e){var i=t[n][1][e];return r(i||e)},i,i.exports)}return e[n].exports}if("function"==typeof __nr_require)return __nr_require;for(var i=0;i<n.length;i++)r(n[i]);return r}({1:[function(t,e,n){function r(){}function i(t,e,n){return function(){return o(t,[u.now()].concat(f(arguments)),e?null:this,n),e?void 0:this}}var o=t("handle"),a=t(8),f=t(9),c=t("ee").get("tracer"),u=t("loader"),s=NREUM;"undefined"==typeof window.newrelic&&(newrelic=s);var d=["setPageViewName","setCustomAttribute","setErrorHandler","finished","addToTrace","inlineHit","addRelease"],p="api-",l=p+"ixn-";a(d,function(t,e){s[e]=i(p+e,!0,"api")}),s.addPageAction=i(p+"addPageAction",!0),s.setCurrentRouteName=i(p+"routeName",!0),e.exports=newrelic,s.interaction=function(){return(new r).get()};var m=r.prototype={createTracer:function(t,e){var n={},r=this,i="function"==typeof e;return o(l+"tracer",[u.now(),t,n],r),function(){if(c.emit((i?"":"no-")+"fn-start",[u.now(),r,i],n),i)try{return e.apply(this,arguments)}catch(t){throw c.emit("fn-err",[arguments,this,t],n),t}finally{c.emit("fn-end",[u.now()],n)}}}};a("actionText,setName,setAttribute,save,ignore,onEnd,getContext,end,get".split(","),function(t,e){m[e]=i(l+e)}),newrelic.noticeError=function(t,e){"string"==typeof t&&(t=new Error(t)),o("err",[t,u.now(),!1,e])}},{}],2:[function(t,e,n){function r(t){if(NREUM.init){for(var e=NREUM.init,n=t.split("."),r=0;r<n.length-1;r++)if(e=e[n[r]],"object"!=typeof e)return;return e=e[n[n.length-1]]}}e.exports={getConfiguration:r}},{}],3:[function(t,e,n){function r(){return f.exists&&performance.now?Math.round(performance.now()):(o=Math.max((new Date).getTime(),o))-a}function i(){return o}var o=(new Date).getTime(),a=o,f=t(10);e.exports=r,e.exports.offset=a,e.exports.getLastTimestamp=i},{}],4:[function(t,e,n){function r(t){return!(!t||!t.protocol||"file:"===t.protocol)}e.exports=r},{}],5:[function(t,e,n){function r(t,e){var n=t.getEntries();n.forEach(function(t){"first-paint"===t.name?d("timing",["fp",Math.floor(t.startTime)]):"first-contentful-paint"===t.name&&d("timing",["fcp",Math.floor(t.startTime)])})}function i(t,e){var n=t.getEntries();n.length>0&&d("lcp",[n[n.length-1]])}function o(t){t.getEntries().forEach(function(t){t.hadRecentInput||d("cls",[t])})}function a(t){if(t instanceof m&&!g){var e=Math.round(t.timeStamp),n={type:t.type};e<=p.now()?n.fid=p.now()-e:e>p.offset&&e<=Date.now()?(e-=p.offset,n.fid=p.now()-e):e=p.now(),g=!0,d("timing",["fi",e,n])}}function f(t){"hidden"===t&&d("pageHide",[p.now()])}if(!("init"in NREUM&&"page_view_timing"in NREUM.init&&"enabled"in NREUM.init.page_view_timing&&NREUM.init.page_view_timing.enabled===!1)){var c,u,s,d=t("handle"),p=t("loader"),l=t(7),m=NREUM.o.EV;if("PerformanceObserver"in window&&"function"==typeof window.PerformanceObserver){c=new PerformanceObserver(r);try{c.observe({entryTypes:["paint"]})}catch(v){}u=new PerformanceObserver(i);try{u.observe({entryTypes:["largest-contentful-paint"]})}catch(v){}s=new PerformanceObserver(o);try{s.observe({type:"layout-shift",buffered:!0})}catch(v){}}if("addEventListener"in document){var g=!1,h=["click","keydown","mousedown","pointerdown","touchstart"];h.forEach(function(t){document.addEventListener(t,a,!1)})}l(f)}},{}],6:[function(t,e,n){function r(t,e){if(!i)return!1;if(t!==i)return!1;if(!e)return!0;if(!o)return!1;for(var n=o.split("."),r=e.split("."),a=0;a<r.length;a++)if(r[a]!==n[a])return!1;return!0}var i=null,o=null,a=/Version\/(\S+)\s+Safari/;if(navigator.userAgent){var f=navigator.userAgent,c=f.match(a);c&&f.indexOf("Chrome")===-1&&f.indexOf("Chromium")===-1&&(i="Safari",o=c[1])}e.exports={agent:i,version:o,match:r}},{}],7:[function(t,e,n){function r(t){function e(){t(a&&document[a]?document[a]:document[i]?"hidden":"visible")}"addEventListener"in document&&o&&document.addEventListener(o,e,!1)}e.exports=r;var i,o,a;"undefined"!=typeof document.hidden?(i="hidden",o="visibilitychange",a="visibilityState"):"undefined"!=typeof document.msHidden?(i="msHidden",o="msvisibilitychange"):"undefined"!=typeof document.webkitHidden&&(i="webkitHidden",o="webkitvisibilitychange",a="webkitVisibilityState")},{}],8:[function(t,e,n){function r(t,e){var n=[],r="",o=0;for(r in t)i.call(t,r)&&(n[o]=e(r,t[r]),o+=1);return n}var i=Object.prototype.hasOwnProperty;e.exports=r},{}],9:[function(t,e,n){function r(t,e,n){e||(e=0),"undefined"==typeof n&&(n=t?t.length:0);for(var r=-1,i=n-e||0,o=Array(i<0?0:i);++r<i;)o[r]=t[e+r];return o}e.exports=r},{}],10:[function(t,e,n){e.exports={exists:"undefined"!=typeof window.performance&&window.performance.timing&&"undefined"!=typeof window.performance.timing.navigationStart}},{}],ee:[function(t,e,n){function r(){}function i(t){function e(t){return t&&t instanceof r?t:t?u(t,c,a):a()}function n(n,r,i,o,a){if(a!==!1&&(a=!0),!l.aborted||o){t&&a&&t(n,r,i);for(var f=e(i),c=v(n),u=c.length,s=0;s<u;s++)c[s].apply(f,r);var p=d[w[n]];return p&&p.push([b,n,r,f]),f}}function o(t,e){y[t]=v(t).concat(e)}function m(t,e){var n=y[t];if(n)for(var r=0;r<n.length;r++)n[r]===e&&n.splice(r,1)}function v(t){return y[t]||[]}function g(t){return p[t]=p[t]||i(n)}function h(t,e){l.aborted||s(t,function(t,n){e=e||"feature",w[n]=e,e in d||(d[e]=[])})}var y={},w={},b={on:o,addEventListener:o,removeEventListener:m,emit:n,get:g,listeners:v,context:e,buffer:h,abort:f,aborted:!1};return b}function o(t){return u(t,c,a)}function a(){return new r}function f(){(d.api||d.feature)&&(l.aborted=!0,d=l.backlog={})}var c="nr@context",u=t("gos"),s=t(8),d={},p={},l=e.exports=i();e.exports.getOrSetContext=o,l.backlog=d},{}],gos:[function(t,e,n){function r(t,e,n){if(i.call(t,e))return t[e];var r=n();if(Object.defineProperty&&Object.keys)try{return Object.defineProperty(t,e,{value:r,writable:!0,enumerable:!1}),r}catch(o){}return t[e]=r,r}var i=Object.prototype.hasOwnProperty;e.exports=r},{}],handle:[function(t,e,n){function r(t,e,n,r){i.buffer([t],r),i.emit(t,e,n)}var i=t("ee").get("handle");e.exports=r,r.ee=i},{}],id:[function(t,e,n){function r(t){var e=typeof t;return!t||"object"!==e&&"function"!==e?-1:t===window?0:a(t,o,function(){return i++})}var i=1,o="nr@id",a=t("gos");e.exports=r},{}],loader:[function(t,e,n){function r(){if(!R++){var t=M.info=NREUM.info,e=v.getElementsByTagName("script")[0];if(setTimeout(u.abort,3e4),!(t&&t.licenseKey&&t.applicationID&&e))return u.abort();c(E,function(e,n){t[e]||(t[e]=n)});var n=a();f("mark",["onload",n+M.offset],null,"api"),f("timing",["load",n]);var r=v.createElement("script");0===t.agent.indexOf("http://")||0===t.agent.indexOf("https://")?r.src=t.agent:r.src=l+"://"+t.agent,e.parentNode.insertBefore(r,e)}}function i(){"complete"===v.readyState&&o()}function o(){f("mark",["domContent",a()+M.offset],null,"api")}var a=t(3),f=t("handle"),c=t(8),u=t("ee"),s=t(6),d=t(4),p=t(2),l=p.getConfiguration("ssl")===!1?"http":"https",m=window,v=m.document,g="addEventListener",h="attachEvent",y=m.XMLHttpRequest,w=y&&y.prototype,b=!d(m.location);NREUM.o={ST:setTimeout,SI:m.setImmediate,CT:clearTimeout,XHR:y,REQ:m.Request,EV:m.Event,PR:m.Promise,MO:m.MutationObserver};var x=""+location,E={beacon:"bam.nr-data.net",errorBeacon:"bam.nr-data.net",agent:"js-agent.newrelic.com/nr-1211.min.js"},O=y&&w&&w[g]&&!/CriOS/.test(navigator.userAgent),M=e.exports={offset:a.getLastTimestamp(),now:a,origin:x,features:{},xhrWrappable:O,userAgent:s,disabled:b};if(!b){t(1),t(5),v[g]?(v[g]("DOMContentLoaded",o,!1),m[g]("load",r,!1)):(v[h]("onreadystatechange",i),m[h]("onload",r)),f("mark",["firstbyte",a.getLastTimestamp()],null,"api");var R=0}},{}],"wrap-function":[function(t,e,n){function r(t,e){function n(e,n,r,c,u){function nrWrapper(){var o,a,s,p;try{a=this,o=d(arguments),s="function"==typeof r?r(o,a):r||{}}catch(l){i([l,"",[o,a,c],s],t)}f(n+"start",[o,a,c],s,u);try{return p=e.apply(a,o)}catch(m){throw f(n+"err",[o,a,m],s,u),m}finally{f(n+"end",[o,a,p],s,u)}}return a(e)?e:(n||(n=""),nrWrapper[p]=e,o(e,nrWrapper,t),nrWrapper)}function r(t,e,r,i,o){r||(r="");var f,c,u,s="-"===r.charAt(0);for(u=0;u<e.length;u++)c=e[u],f=t[c],a(f)||(t[c]=n(f,s?c+r:r,i,c,o))}function f(n,r,o,a){if(!m||e){var f=m;m=!0;try{t.emit(n,r,o,e,a)}catch(c){i([c,n,r,o],t)}m=f}}return t||(t=s),n.inPlace=r,n.flag=p,n}function i(t,e){e||(e=s);try{e.emit("internal-error",t)}catch(n){}}function o(t,e,n){if(Object.defineProperty&&Object.keys)try{var r=Object.keys(t);return r.forEach(function(n){Object.defineProperty(e,n,{get:function(){return t[n]},set:function(e){return t[n]=e,e}})}),e}catch(o){i([o],n)}for(var a in t)l.call(t,a)&&(e[a]=t[a]);return e}function a(t){return!(t&&t instanceof Function&&t.apply&&!t[p])}function f(t,e){var n=e(t);return n[p]=t,o(t,n,s),n}function c(t,e,n){var r=t[e];t[e]=f(r,n)}function u(){for(var t=arguments.length,e=new Array(t),n=0;n<t;++n)e[n]=arguments[n];return e}var s=t("ee"),d=t(9),p="nr@original",l=Object.prototype.hasOwnProperty,m=!1;e.exports=r,e.exports.wrapFunction=f,e.exports.wrapInPlace=c,e.exports.argsToArray=u},{}]},{},["loader"]);</script> <link rel="revision" href="https://www.epa.gov/uic/class-ii-oil-and-gas-related-injection-wells"/> <title>Class II Oil and Gas Related Injection Wells | US EPA</title> <link rel="icon" type="image/x-icon" href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/favicon.ico"> <meta name="msapplication-TileColor" content="#FFFFFF"> <meta name="msapplication-TileImage" content="/themes/epa_theme/images/favicon-144.png"> <meta name="application-name" content=""> <meta name="msapplication-config" content="/themes/epa_theme/images/ieconfig.xml"> <link rel="apple-touch-icon-precomposed" sizes="196x196" href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/favicon-196.png"> <link rel="apple-touch-icon-precomposed" sizes="152x152" href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/favicon-152.png"> <link rel="apple-touch-icon-precomposed" sizes="144x144" href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/favicon-144.png"> <link rel="apple-touch-icon-precomposed" sizes="120x120" href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/favicon-120.png"> <link rel="apple-touch-icon-precomposed" sizes="114x114" href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/favicon-114.png"> <link rel="apple-touch-icon-precomposed" sizes="72x72" href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/favicon-72.png"> <link rel="apple-touch-icon-precomposed" href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/favicon-180.png"> <link rel="icon" href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/favicon-32.png" sizes="32x32"> <link rel="preload" href="/web/20211028015312/https://www.epa.gov/themes/epa_theme/fonts/source-sans-pro/sourcesanspro-regular-webfont.woff2" as="font" crossorigin="anonymous"> <link rel="preload" href="/web/20211028015312/https://www.epa.gov/themes/epa_theme/fonts/source-sans-pro/sourcesanspro-bold-webfont.woff2" as="font" crossorigin="anonymous"> <link rel="preload" href="/web/20211028015312/https://www.epa.gov/themes/epa_theme/fonts/merriweather/Latin-Merriweather-Bold.woff2" as="font" crossorigin="anonymous"> <link rel="stylesheet" media="all" href="/web/20211028015312cs_/https://www.epa.gov/core/themes/stable/css/system/components/ajax-progress.module.css?r0y0d3"/> <link rel="stylesheet" media="all" href="/web/20211028015312cs_/https://www.epa.gov/core/themes/stable/css/system/components/autocomplete-loading.module.css?r0y0d3"/> <link rel="stylesheet" media="all" href="/web/20211028015312cs_/https://www.epa.gov/core/themes/stable/css/system/components/js.module.css?r0y0d3"/> <link rel="stylesheet" media="all" href="/web/20211028015312cs_/https://www.epa.gov/core/themes/stable/css/system/components/sticky-header.module.css?r0y0d3"/> <link rel="stylesheet" media="all" href="/web/20211028015312cs_/https://www.epa.gov/core/themes/stable/css/system/components/system-status-counter.css?r0y0d3"/> <link rel="stylesheet" media="all" href="/web/20211028015312cs_/https://www.epa.gov/core/themes/stable/css/system/components/system-status-report-counters.css?r0y0d3"/> <link rel="stylesheet" media="all" href="/web/20211028015312cs_/https://www.epa.gov/core/themes/stable/css/system/components/system-status-report-general-info.css?r0y0d3"/> <link rel="stylesheet" media="all" href="/web/20211028015312cs_/https://www.epa.gov/core/themes/stable/css/system/components/tabledrag.module.css?r0y0d3"/> <link rel="stylesheet" media="all" href="/web/20211028015312cs_/https://www.epa.gov/core/themes/stable/css/system/components/tablesort.module.css?r0y0d3"/> <link rel="stylesheet" media="all" href="/web/20211028015312cs_/https://www.epa.gov/core/themes/stable/css/system/components/tree-child.module.css?r0y0d3"/> <link rel="stylesheet" media="all" href="/web/20211028015312cs_/https://www.epa.gov/core/themes/stable/css/filter/filter.caption.css?r0y0d3"/> <link rel="stylesheet" media="all" href="/web/20211028015312cs_/https://www.epa.gov/core/themes/stable/css/media/filter.caption.css?r0y0d3"/> <link rel="stylesheet" media="all" href="/web/20211028015312cs_/https://www.epa.gov/modules/contrib/paragraphs/css/paragraphs.unpublished.css?r0y0d3"/> <link rel="stylesheet" media="all" href="/web/20211028015312cs_/https://www.epa.gov/themes/epa_theme/css/styles.css?r0y0d3"/> <link rel="stylesheet" media="all" href="/web/20211028015312cs_/https://www.epa.gov/themes/epa_theme/css-lib/colorbox.min.css?r0y0d3"/>  <script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start': new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0], j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src= 'https://web.archive.org/web/20211028015312/https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f); })(window,document,'script','dataLayer','GTM-L8ZB');</script>  </head> <body class="path-node not-front node-page node-page--node-type-page" id="top"> <div class="skiplinks" role="navigation" aria-labelledby="skip-to-main"> <a id="skip-to-main" href="#main" class="skiplinks__link visually-hidden focusable">Skip to main content</a> </div>  <noscript><iframe src="https://web.archive.org/web/20211028015312if_/https://www.googletagmanager.com/ns.html?id=GTM-L8ZB" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>  <div class="dialog-off-canvas-main-canvas" data-off-canvas-main-canvas> <section class="usa-banner" aria-label="Official government website"> <div class="usa-accordion"> <header class="usa-banner__header"> <div class="usa-banner__inner"> <div class="grid-col-auto"> <img class="usa-banner__header-flag" src="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/us_flag_small.png" alt="U.S. flag"/> </div> <div class="grid-col-fill tablet:grid-col-auto"> <p class="usa-banner__header-text">An official website of the United States government</p> <p class="usa-banner__header-action" aria-hidden="true">Here’s how you know</p></div> <button class="usa-accordion__button usa-banner__button" aria-expanded="false" aria-controls="gov-banner"> <span class="usa-banner__button-text">Here’s how you know</span> </button> </div> </header> <div class="usa-banner__content usa-accordion__content" id="gov-banner"> <div class="grid-row grid-gap-lg"> <div class="usa-banner__guidance tablet:grid-col-6"> <img class="usa-banner__icon usa-media-block__img" src="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/icon-dot-gov.svg" alt="Dot gov"> <div class="usa-media-block__body"> <p> <strong>Official websites use .gov</strong> <br> A <strong>.gov</strong> website belongs to an official government organization in the United States. </p> </div> </div> <div class="usa-banner__guidance tablet:grid-col-6"> <img class="usa-banner__icon usa-media-block__img" src="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/icon-https.svg" alt="HTTPS"> <div class="usa-media-block__body"> <p> <strong>Secure .gov websites use HTTPS</strong> <br> A <strong>lock</strong> (<span class="icon-lock"><svg xmlns="http://www.w3.org/2000/svg" width="52" height="64" viewbox="0 0 52 64" class="usa-banner__lock-image" role="img" aria-labelledby="banner-lock-title banner-lock-description"><title id="banner-lock-title">Lock</title><desc id="banner-lock-description">A locked padlock</desc><path fill="#000000" fill-rule="evenodd" d="M26 0c10.493 0 19 8.507 19 19v9h3a4 4 0 0 1 4 4v28a4 4 0 0 1-4 4H4a4 4 0 0 1-4-4V32a4 4 0 0 1 4-4h3v-9C7 8.507 15.507 0 26 0zm0 8c-5.979 0-10.843 4.77-10.996 10.712L15 19v9h22v-9c0-6.075-4.925-11-11-11z"/></svg></span>) or <strong>https://</strong> means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. </p> </div> </div> </div> </div> </div> </section> <div> <div class="js-view-dom-id-epa-alerts--public"> <noscript> <div class="usa-site-alert usa-site-alert--info"> <div class="usa-alert"> <div class="usa-alert__body"> <div class="usa-alert__text"> <p>JavaScript appears to be disabled on this computer. Please <a href="/web/20211028015312/https://www.epa.gov/alerts">click here to see any active alerts</a>.</p> </div> </div> </div> </div> </noscript> </div> </div> <div class="usa-overlay"></div> <header class="l-header"> <div class="l-constrain"> <div class="l-header__navbar"> <div class="l-header__branding"> <a class="site-logo" href="/web/20211028015312/https://www.epa.gov/" aria-label="Home" title="Home" rel="home"> <span class="site-logo__image"> <svg class="site-logo__svg" viewbox="0 0 1061 147" aria-hidden="true" xmlns="http://www.w3.org/2000/svg"> <path d="M112.8 53.5C108 72.1 89.9 86.8 69.9 86.8c-20.1 0-38-14.7-42.9-33.4h.2s9.8 10.3-.2 0c3.1 3.1 6.2 4.4 10.7 4.4s7.7-1.3 10.7-4.4c3.1 3.1 6.3 4.5 10.9 4.4 4.5 0 7.6-1.3 10.7-4.4 3.1 3.1 6.2 4.4 10.7 4.4 4.5 0 7.7-1.3 10.7-4.4 3.1 3.1 6.3 4.5 10.9 4.4 4.3 0 7.4-1.2 10.5-4.3zM113.2 43.5c0-24-19.4-43.5-43.3-43.5-24 0-43.5 19.5-43.5 43.5h39.1c-4.8-1.8-8.1-6.3-8.1-11.6 0-7 5.7-12.5 12.5-12.5 7 0 12.7 5.5 12.7 12.5 0 5.2-3.1 9.6-7.6 11.6h38.2zM72.6 139.3c.7-36.9 29.7-68.8 66.9-70 0 37.2-30 68-66.9 70zM67.1 139.3c-.7-36.9-29.7-68.8-67.1-70 0 37.2 30.2 68 67.1 70zM240 3.1h-87.9v133.1H240v-20.4h-60.3v-36H240v-21h-60.3v-35H240V3.1zM272.8 58.8h27.1c9.1 0 15.2-8.6 15.1-17.7-.1-9-6.1-17.3-15.1-17.3h-25.3v112.4h-27.8V3.1h62.3c20.2 0 35 17.8 35.2 38 .2 20.4-14.8 38.7-35.2 38.7h-36.3v-21zM315.9 136.2h29.7l12.9-35h54.2l-8.1-21.9h-38.4l18.9-50.7 39.2 107.6H454L400.9 3.1h-33.7l-51.3 133.1zM473.3.8v22.4c0 1.9.2 3.3.5 4.3s.7 1.7 1 2.2c1.2 1.4 2.5 2.4 3.9 2.9 1.5.5 2.8.7 4.1.7 2.4 0 4.2-.4 5.5-1.3 1.3-.8 2.2-1.8 2.8-2.9.6-1.1.9-2.3 1-3.4.1-1.1.1-2 .1-2.6V.8h4.7v24c0 .7-.1 1.5-.4 2.4-.3 1.8-1.2 3.6-2.5 5.4-1.8 2.1-3.8 3.5-6 4.2-2.2.6-4 .9-5.3.9-1.8 0-3.8-.3-6.2-1.1-2.4-.8-4.5-2.3-6.2-4.7-.5-.8-1-1.8-1.4-3.2-.4-1.3-.6-3.3-.6-5.9V.8h5zM507.5 14.5v-2.9l4.6.1-.1 4.1c.2-.3.4-.7.8-1.2.3-.5.8-.9 1.4-1.4.6-.5 1.4-.9 2.3-1.3.9-.3 2.1-.5 3.4-.4.6 0 1.4.1 2.4.3.9.2 1.9.6 2.9 1.2s1.8 1.5 2.4 2.6c.6 1.2.9 2.8.9 4.7l-.4 17-4.6-.1.4-16c0-.9 0-1.7-.2-2.4-.1-.7-.5-1.3-1.1-1.9-1.2-1.2-2.6-1.8-4.3-1.8-1.7 0-3.1.5-4.4 1.7-1.3 1.2-2 3.1-2.1 5.7l-.3 14.5-4.5-.1.5-22.4zM537.2.9h5.5V6h-5.5V.9m.5 10.9h4.6v25.1h-4.6V11.8zM547.8 11.7h4.3V6.4l4.5-1.5v6.8h5.4v3.4h-5.4v15.1c0 .3 0 .6.1 1 0 .4.1.7.4 1.1.2.4.5.6 1 .8.4.3 1 .4 1.8.4 1 0 1.7-.1 2.2-.2V37c-.9.2-2.1.3-3.8.3-2.1 0-3.6-.4-4.6-1.2-1-.8-1.5-2.2-1.5-4.2V15.1h-4.3v-3.4zM570.9 25.2c-.1 2.6.5 4.8 1.7 6.5 1.1 1.7 2.9 2.6 5.3 2.6 1.5 0 2.8-.4 3.9-1.3 1-.8 1.6-2.2 1.8-4h4.6c0 .6-.2 1.4-.4 2.3-.3 1-.8 2-1.7 3-.2.3-.6.6-1 1-.5.4-1 .7-1.7 1.1-.7.4-1.5.6-2.4.8-.9.3-2 .4-3.3.4-7.6-.2-11.3-4.5-11.3-12.9 0-2.5.3-4.8 1-6.8s2-3.7 3.8-5.1c1.2-.8 2.4-1.3 3.7-1.6 1.3-.2 2.2-.3 3-.3 2.7 0 4.8.6 6.3 1.6s2.5 2.3 3.1 3.9c.6 1.5 1 3.1 1.1 4.6.1 1.6.1 2.9 0 4h-17.5m12.9-3v-1.1c0-.4 0-.8-.1-1.2-.1-.9-.4-1.7-.8-2.5s-1-1.5-1.8-2c-.9-.5-2-.8-3.4-.8-.8 0-1.5.1-2.3.3-.8.2-1.5.7-2.2 1.3-.7.6-1.2 1.3-1.6 2.3-.4 1-.7 2.2-.8 3.6h13zM612.9.9h4.6V33c0 1 .1 2.3.2 4h-4.6l-.1-4c-.2.3-.4.7-.7 1.2-.3.5-.8 1-1.4 1.5-1 .7-2 1.2-3.1 1.4l-1.5.3c-.5.1-.9.1-1.4.1-.4 0-.8 0-1.3-.1s-1.1-.2-1.7-.3c-1.1-.3-2.3-.9-3.4-1.8s-2.1-2.2-2.9-3.8c-.8-1.7-1.2-3.9-1.2-6.6.1-4.8 1.2-8.3 3.4-10.5 2.1-2.1 4.7-3.2 7.6-3.2 1.3 0 2.4.2 3.4.5.9.3 1.6.7 2.2 1.2.6.4 1 .9 1.3 1.4.3.5.6.8.7 1.1V.9m0 23.1c0-1.9-.2-3.3-.5-4.4-.4-1.1-.8-2-1.4-2.6-.5-.7-1.2-1.3-2-1.8-.9-.5-2-.7-3.3-.7-1.7 0-2.9.5-3.8 1.3-.9.8-1.6 1.9-2 3.1-.4 1.2-.7 2.3-.7 3.4-.1 1.1-.2 1.9-.1 2.4 0 1.1.1 2.2.3 3.4.2 1.1.5 2.2 1 3.1.5 1 1.2 1.7 2 2.3.9.6 2 .9 3.3.9 1.8 0 3.2-.5 4.2-1.4 1-.8 1.7-1.8 2.1-3 .4-1.2.7-2.4.8-3.4.1-1.4.1-2.1.1-2.6zM643.9 26.4c0 .6.1 1.3.3 2.1.1.8.5 1.6 1 2.3.5.8 1.4 1.4 2.5 1.9s2.7.8 4.7.8c1.8 0 3.3-.3 4.4-.8 1.1-.5 1.9-1.1 2.5-1.8.6-.7 1-1.5 1.1-2.2.1-.7.2-1.2.2-1.7 0-1-.2-1.9-.5-2.6-.4-.6-.9-1.2-1.6-1.6-1.4-.8-3.4-1.4-5.9-2-4.9-1.1-8.1-2.2-9.5-3.2-1.4-1-2.3-2.2-2.9-3.5-.6-1.2-.8-2.4-.8-3.6.1-3.7 1.5-6.4 4.2-8.1 2.6-1.7 5.7-2.5 9.1-2.5 1.3 0 2.9.2 4.8.5 1.9.4 3.6 1.4 5 3 .5.5.9 1.1 1.2 1.7.3.5.5 1.1.6 1.6.2 1.1.3 2.1.3 2.9h-5c-.2-2.2-1-3.7-2.4-4.5-1.5-.7-3.1-1.1-4.9-1.1-5.1.1-7.7 2-7.8 5.8 0 1.5.5 2.7 1.6 3.5 1 .8 2.6 1.4 4.7 1.9 4 1 6.7 1.8 8.1 2.2.8.2 1.4.5 1.8.7.5.2 1 .5 1.4.9.8.5 1.4 1.1 1.9 1.8s.8 1.4 1.1 2.1c.3 1.4.5 2.5.5 3.4 0 3.3-1.2 6-3.5 8-2.3 2.1-5.8 3.2-10.3 3.3-1.4 0-3.2-.3-5.4-.8-1-.3-2-.7-3-1.2-.9-.5-1.8-1.2-2.5-2.1-.9-1.4-1.5-2.7-1.7-4.1-.3-1.3-.4-2.4-.3-3.2h5zM670 11.7h4.3V6.4l4.5-1.5v6.8h5.4v3.4h-5.4v15.1c0 .3 0 .6.1 1 0 .4.1.7.4 1.1.2.4.5.6 1 .8.4.3 1 .4 1.8.4 1 0 1.7-.1 2.2-.2V37c-.9.2-2.1.3-3.8.3-2.1 0-3.6-.4-4.6-1.2-1-.8-1.5-2.2-1.5-4.2V15.1H670v-3.4zM705.3 36.9c-.3-1.2-.5-2.5-.4-3.7-.5 1-1.1 1.8-1.7 2.4-.7.6-1.4 1.1-2 1.4-1.4.5-2.7.8-3.7.8-2.8 0-4.9-.8-6.4-2.2-1.5-1.4-2.2-3.1-2.2-5.2 0-1 .2-2.3.8-3.7.6-1.4 1.7-2.6 3.5-3.7 1.4-.7 2.9-1.2 4.5-1.5 1.6-.1 2.9-.2 3.9-.2s2.1 0 3.3.1c.1-2.9-.2-4.8-.9-5.6-.5-.6-1.1-1.1-1.9-1.3-.8-.2-1.6-.4-2.3-.4-1.1 0-2 .2-2.6.5-.7.3-1.2.7-1.5 1.2-.3.5-.5.9-.6 1.4-.1.5-.2.9-.2 1.2h-4.6c.1-.7.2-1.4.4-2.3.2-.8.6-1.6 1.3-2.5.5-.6 1-1 1.7-1.3.6-.3 1.3-.6 2-.8 1.5-.4 2.8-.6 4.2-.6 1.8 0 3.6.3 5.2.9 1.6.6 2.8 1.6 3.4 2.9.4.7.6 1.4.7 2 .1.6.1 1.2.1 1.8l-.2 12c0 1 .1 3.1.4 6.3h-4.2m-.5-12.1c-.7-.1-1.6-.1-2.6-.1h-2.1c-1 .1-2 .3-3 .6s-1.9.8-2.6 1.5c-.8.7-1.2 1.7-1.2 3 0 .4.1.8.2 1.3s.4 1 .8 1.5.9.8 1.6 1.1c.7.3 1.5.5 2.5.5 2.3 0 4.1-.9 5.2-2.7.5-.8.8-1.7 1-2.7.1-.9.2-2.2.2-4zM714.5 11.7h4.3V6.4l4.5-1.5v6.8h5.4v3.4h-5.4v15.1c0 .3 0 .6.1 1 0 .4.1.7.4 1.1.2.4.5.6 1 .8.4.3 1 .4 1.8.4 1 0 1.7-.1 2.2-.2V37c-.9.2-2.1.3-3.8.3-2.1 0-3.6-.4-4.6-1.2-1-.8-1.5-2.2-1.5-4.2V15.1h-4.3v-3.4zM737.6 25.2c-.1 2.6.5 4.8 1.7 6.5 1.1 1.7 2.9 2.6 5.3 2.6 1.5 0 2.8-.4 3.9-1.3 1-.8 1.6-2.2 1.8-4h4.6c0 .6-.2 1.4-.4 2.3-.3 1-.8 2-1.7 3-.2.3-.6.6-1 1-.5.4-1 .7-1.7 1.1-.7.4-1.5.6-2.4.8-.9.3-2 .4-3.3.4-7.6-.2-11.3-4.5-11.3-12.9 0-2.5.3-4.8 1-6.8s2-3.7 3.8-5.1c1.2-.8 2.4-1.3 3.7-1.6 1.3-.2 2.2-.3 3-.3 2.7 0 4.8.6 6.3 1.6s2.5 2.3 3.1 3.9c.6 1.5 1 3.1 1.1 4.6.1 1.6.1 2.9 0 4h-17.5m12.9-3v-1.1c0-.4 0-.8-.1-1.2-.1-.9-.4-1.7-.8-2.5s-1-1.5-1.8-2c-.9-.5-2-.8-3.4-.8-.8 0-1.5.1-2.3.3-.8.2-1.5.7-2.2 1.3-.7.6-1.2 1.3-1.6 2.3-.4 1-.7 2.2-.8 3.6h13zM765.3 29.5c0 .5.1 1 .2 1.4.1.5.4 1 .8 1.5s.9.8 1.6 1.1c.7.3 1.6.5 2.7.5 1 0 1.8-.1 2.5-.3.7-.2 1.3-.6 1.7-1.2.5-.7.8-1.5.8-2.4 0-1.2-.4-2-1.3-2.5s-2.2-.9-4.1-1.2c-1.3-.3-2.4-.6-3.6-1-1.1-.3-2.1-.8-3-1.3-.9-.5-1.5-1.2-2-2.1-.5-.8-.8-1.9-.8-3.2 0-2.4.9-4.2 2.6-5.6 1.7-1.3 4-2 6.8-2.1 1.6 0 3.3.3 5 .8 1.7.6 2.9 1.6 3.7 3.1.4 1.4.6 2.6.6 3.7h-4.6c0-1.8-.6-3-1.7-3.5-1.1-.4-2.1-.6-3.1-.6h-1c-.5 0-1.1.2-1.7.4-.6.2-1.1.5-1.5 1.1-.5.5-.7 1.2-.7 2.1 0 1.1.5 1.9 1.3 2.3.7.4 1.5.7 2.1.9 3.3.7 5.6 1.3 6.9 1.8 1.3.4 2.2 1 2.8 1.7.7.7 1.1 1.4 1.4 2.2.3.8.4 1.6.4 2.5 0 1.4-.3 2.7-.9 3.8-.6 1.1-1.4 2-2.4 2.6-1.1.6-2.2 1-3.4 1.3-1.2.3-2.5.4-3.8.4-2.5 0-4.7-.6-6.6-1.8-1.8-1.2-2.8-3.3-2.9-6.3h5.2zM467.7 50.8h21.9V55h-17.1v11.3h16.3v4.2h-16.3v12.1H490v4.3h-22.3zM499 64.7l-.1-2.9h4.6v4.1c.2-.3.4-.8.7-1.2.3-.5.8-1 1.3-1.5.6-.5 1.4-1 2.3-1.3.9-.3 2-.5 3.4-.5.6 0 1.4.1 2.4.2.9.2 1.9.5 2.9 1.1 1 .6 1.8 1.4 2.5 2.5.6 1.2 1 2.7 1 4.7V87h-4.6V71c0-.9-.1-1.7-.2-2.4-.2-.7-.5-1.3-1.1-1.9-1.2-1.1-2.6-1.7-4.3-1.7-1.7 0-3.1.6-4.3 1.8-1.3 1.2-2 3.1-2 5.7V87H499V64.7zM524.6 61.8h5.1l7.7 19.9 7.6-19.9h5l-10.6 25.1h-4.6zM555.7 50.9h5.5V56h-5.5v-5.1m.5 10.9h4.6v25.1h-4.6V61.8zM570.3 67c0-1.8-.1-3.5-.3-5.1h4.6l.1 4.9c.5-1.8 1.4-3 2.5-3.7 1.1-.7 2.2-1.2 3.3-1.3 1.4-.2 2.4-.2 3.1-.1v4.6c-.2-.1-.5-.2-.9-.2h-1.3c-1.3 0-2.4.2-3.3.5-.9.4-1.5.9-2 1.6-.9 1.4-1.4 3.2-1.3 5.4v13.3h-4.6V67zM587.6 74.7c0-1.6.2-3.2.6-4.8.4-1.6 1.1-3 2-4.4 1-1.3 2.2-2.4 3.8-3.2 1.6-.8 3.6-1.2 5.9-1.2 2.4 0 4.5.4 6.1 1.3 1.5.9 2.7 2 3.6 3.3.9 1.3 1.5 2.8 1.8 4.3.2.8.3 1.5.4 2.2v2.2c0 3.7-1 6.9-3 9.5-2 2.6-5.1 4-9.3 4-4-.1-7-1.4-9-3.9-1.9-2.5-2.9-5.6-2.9-9.3m4.8-.3c0 2.7.6 5 1.8 6.9 1.2 2 3 3 5.6 3.1.9 0 1.8-.2 2.7-.5.8-.3 1.6-.9 2.3-1.7.7-.8 1.3-1.9 1.8-3.2.4-1.3.6-2.9.6-4.7-.1-6.4-2.5-9.6-7.1-9.6-.7 0-1.5.1-2.4.3-.8.3-1.7.8-2.5 1.6-.8.7-1.4 1.7-1.9 3-.6 1.1-.9 2.8-.9 4.8zM620.2 64.7l-.1-2.9h4.6v4.1c.2-.3.4-.8.7-1.2.3-.5.8-1 1.3-1.5.6-.5 1.4-1 2.3-1.3.9-.3 2-.5 3.4-.5.6 0 1.4.1 2.4.2.9.2 1.9.5 2.9 1.1 1 .6 1.8 1.4 2.5 2.5.6 1.2 1 2.7 1 4.7V87h-4.6V71c0-.9-.1-1.7-.2-2.4-.2-.7-.5-1.3-1.1-1.9-1.2-1.1-2.6-1.7-4.3-1.7-1.7 0-3.1.6-4.3 1.8-1.3 1.2-2 3.1-2 5.7V87h-4.6V64.7zM650 65.1l-.1-3.3h4.6v3.6c1.2-1.9 2.6-3.2 4.1-3.7 1.5-.4 2.7-.6 3.8-.6 1.4 0 2.6.2 3.6.5.9.3 1.7.7 2.3 1.1 1.1 1 1.9 2 2.3 3.1.2-.4.5-.8 1-1.3.4-.5.9-1 1.5-1.6.6-.5 1.5-.9 2.5-1.3 1-.3 2.2-.5 3.5-.5.9 0 1.9.1 3 .3 1 .2 2 .7 3 1.3 1 .6 1.7 1.5 2.3 2.7.6 1.2.9 2.7.9 4.6v16.9h-4.6V70.7c0-1.1-.1-2-.2-2.5-.1-.6-.3-1-.6-1.3-.4-.6-1-1.2-1.8-1.6-.8-.4-1.8-.6-3.1-.6-1.5 0-2.7.4-3.6 1-.4.3-.8.5-1.1.9l-.8.8c-.5.8-.8 1.8-1 2.8-.1 1.1-.2 2-.1 2.6v14.1h-4.6V70.2c0-1.6-.5-2.9-1.4-4-.9-1-2.3-1.5-4.2-1.5-1.6 0-2.9.4-3.8 1.1-.9.7-1.5 1.2-1.8 1.7-.5.7-.8 1.5-.9 2.5-.1.9-.2 1.8-.2 2.6v14.3H650V65.1zM700.5 75.2c-.1 2.6.5 4.8 1.7 6.5 1.1 1.7 2.9 2.6 5.3 2.6 1.5 0 2.8-.4 3.9-1.3 1-.8 1.6-2.2 1.8-4h4.6c0 .6-.2 1.4-.4 2.3-.3 1-.8 2-1.7 3-.2.3-.6.6-1 1-.5.4-1 .7-1.7 1.1-.7.4-1.5.6-2.4.8-.9.3-2 .4-3.3.4-7.6-.2-11.3-4.5-11.3-12.9 0-2.5.3-4.8 1-6.8s2-3.7 3.8-5.1c1.2-.8 2.4-1.3 3.7-1.6 1.3-.2 2.2-.3 3-.3 2.7 0 4.8.6 6.3 1.6s2.5 2.3 3.1 3.9c.6 1.5 1 3.1 1.1 4.6.1 1.6.1 2.9 0 4h-17.5m12.8-3v-1.1c0-.4 0-.8-.1-1.2-.1-.9-.4-1.7-.8-2.5s-1-1.5-1.8-2c-.9-.5-2-.8-3.4-.8-.8 0-1.5.1-2.3.3-.8.2-1.5.7-2.2 1.3-.7.6-1.2 1.3-1.6 2.3-.4 1-.7 2.2-.8 3.6h13zM725.7 64.7l-.1-2.9h4.6v4.1c.2-.3.4-.8.7-1.2.3-.5.8-1 1.3-1.5.6-.5 1.4-1 2.3-1.3.9-.3 2-.5 3.4-.5.6 0 1.4.1 2.4.2.9.2 1.9.5 2.9 1.1 1 .6 1.8 1.4 2.5 2.5.6 1.2 1 2.7 1 4.7V87h-4.6V71c0-.9-.1-1.7-.2-2.4-.2-.7-.5-1.3-1.1-1.9-1.2-1.1-2.6-1.7-4.3-1.7-1.7 0-3.1.6-4.3 1.8-1.3 1.2-2 3.1-2 5.7V87h-4.6V64.7zM752.3 61.7h4.3v-5.2l4.5-1.5v6.8h5.4v3.4h-5.4v15.1c0 .3 0 .6.1 1 0 .4.1.7.4 1.1.2.4.5.6 1 .8.4.3 1 .4 1.8.4 1 0 1.7-.1 2.2-.2V87c-.9.2-2.1.3-3.8.3-2.1 0-3.6-.4-4.6-1.2-1-.8-1.5-2.2-1.5-4.2V65.1h-4.3v-3.4zM787.6 86.9c-.3-1.2-.5-2.5-.4-3.7-.5 1-1.1 1.8-1.7 2.4-.7.6-1.4 1.1-2 1.4-1.4.5-2.7.8-3.7.8-2.8 0-4.9-.8-6.4-2.2-1.5-1.4-2.2-3.1-2.2-5.2 0-1 .2-2.3.8-3.7.6-1.4 1.7-2.6 3.5-3.7 1.4-.7 2.9-1.2 4.5-1.5 1.6-.1 2.9-.2 3.9-.2s2.1 0 3.3.1c.1-2.9-.2-4.8-.9-5.6-.5-.6-1.1-1.1-1.9-1.3-.8-.2-1.6-.4-2.3-.4-1.1 0-2 .2-2.6.5-.7.3-1.2.7-1.5 1.2-.3.5-.5.9-.6 1.4-.1.5-.2.9-.2 1.2h-4.6c.1-.7.2-1.4.4-2.3.2-.8.6-1.6 1.3-2.5.5-.6 1-1 1.7-1.3.6-.3 1.3-.6 2-.8 1.5-.4 2.8-.6 4.2-.6 1.8 0 3.6.3 5.2.9 1.6.6 2.8 1.6 3.4 2.9.4.7.6 1.4.7 2 .1.6.1 1.2.1 1.8l-.2 12c0 1 .1 3.1.4 6.3h-4.2m-.5-12.1c-.7-.1-1.6-.1-2.6-.1h-2.1c-1 .1-2 .3-3 .6s-1.9.8-2.6 1.5c-.8.7-1.2 1.7-1.2 3 0 .4.1.8.2 1.3s.4 1 .8 1.5.9.8 1.6 1.1c.7.3 1.5.5 2.5.5 2.3 0 4.1-.9 5.2-2.7.5-.8.8-1.7 1-2.7.1-.9.2-2.2.2-4zM800.7 50.9h4.6V87h-4.6zM828.4 50.8h11.7c2.1 0 3.9.1 5.5.4.8.2 1.5.4 2.2.9.7.4 1.3.9 1.8 1.6 1.7 1.9 2.6 4.2 2.6 7 0 2.7-.9 5.1-2.8 7.1-.8.9-2 1.7-3.6 2.2-1.6.6-3.9.9-6.9.9h-5.7V87h-4.8V50.8m4.8 15.9h5.8c.8 0 1.7-.1 2.6-.2.9-.1 1.8-.3 2.6-.7.8-.4 1.5-1 2-1.9.5-.8.8-2 .8-3.4s-.2-2.5-.7-3.3c-.5-.8-1.1-1.3-1.9-1.7-1.6-.5-3.1-.8-4.5-.7h-6.8v11.9zM858.1 67c0-1.8-.1-3.5-.3-5.1h4.6l.1 4.9c.5-1.8 1.4-3 2.5-3.7 1.1-.7 2.2-1.2 3.3-1.3 1.4-.2 2.4-.2 3.1-.1v4.6c-.2-.1-.5-.2-.9-.2h-1.3c-1.3 0-2.4.2-3.3.5-.9.4-1.5.9-2 1.6-.9 1.4-1.4 3.2-1.3 5.4v13.3H858V67zM875.5 74.7c0-1.6.2-3.2.6-4.8.4-1.6 1.1-3 2-4.4 1-1.3 2.2-2.4 3.8-3.2 1.6-.8 3.6-1.2 5.9-1.2 2.4 0 4.5.4 6.1 1.3 1.5.9 2.7 2 3.6 3.3.9 1.3 1.5 2.8 1.8 4.3.2.8.3 1.5.4 2.2v2.2c0 3.7-1 6.9-3 9.5-2 2.6-5.1 4-9.3 4-4-.1-7-1.4-9-3.9-1.9-2.5-2.9-5.6-2.9-9.3m4.8-.3c0 2.7.6 5 1.8 6.9 1.2 2 3 3 5.6 3.1.9 0 1.8-.2 2.7-.5.8-.3 1.6-.9 2.3-1.7.7-.8 1.3-1.9 1.8-3.2.4-1.3.6-2.9.6-4.7-.1-6.4-2.5-9.6-7.1-9.6-.7 0-1.5.1-2.4.3-.8.3-1.7.8-2.5 1.6-.8.7-1.4 1.7-1.9 3-.7 1.1-.9 2.8-.9 4.8zM904.1 61.7h4.3v-5.2l4.5-1.5v6.8h5.4v3.4h-5.4v15.1c0 .3 0 .6.1 1 0 .4.1.7.4 1.1.2.4.5.6 1 .8.4.3 1 .4 1.8.4 1 0 1.7-.1 2.2-.2V87c-.9.2-2.1.3-3.8.3-2.1 0-3.6-.4-4.6-1.2-1-.8-1.5-2.2-1.5-4.2V65.1h-4.3v-3.4zM927.2 75.2c-.1 2.6.5 4.8 1.7 6.5 1.1 1.7 2.9 2.6 5.3 2.6 1.5 0 2.8-.4 3.9-1.3 1-.8 1.6-2.2 1.8-4h4.6c0 .6-.2 1.4-.4 2.3-.3 1-.8 2-1.7 3-.2.3-.6.6-1 1-.5.4-1 .7-1.7 1.1-.7.4-1.5.6-2.4.8-.9.3-2 .4-3.3.4-7.6-.2-11.3-4.5-11.3-12.9 0-2.5.3-4.8 1-6.8s2-3.7 3.8-5.1c1.2-.8 2.4-1.3 3.7-1.6 1.3-.2 2.2-.3 3-.3 2.7 0 4.8.6 6.3 1.6s2.5 2.3 3.1 3.9c.6 1.5 1 3.1 1.1 4.6.1 1.6.1 2.9 0 4h-17.5m12.9-3v-1.1c0-.4 0-.8-.1-1.2-.1-.9-.4-1.7-.8-2.5s-1-1.5-1.8-2c-.9-.5-2-.8-3.4-.8-.8 0-1.5.1-2.3.3-.8.2-1.5.7-2.2 1.3-.7.6-1.2 1.3-1.6 2.3-.4 1-.7 2.2-.8 3.6h13zM966.1 69.8c0-.3 0-.8-.1-1.4-.1-.6-.3-1.1-.6-1.8-.2-.6-.7-1.2-1.4-1.6-.7-.4-1.6-.6-2.7-.6-1.5 0-2.7.4-3.5 1.2-.9.8-1.5 1.7-1.9 2.8-.4 1.1-.6 2.2-.7 3.2-.1 1.1-.2 1.8-.1 2.4 0 1.3.1 2.5.3 3.7.2 1.2.5 2.3.9 3.3.8 2 2.4 3 4.8 3.1 1.9 0 3.3-.7 4.1-1.9.8-1.1 1.2-2.3 1.2-3.6h4.6c-.2 2.5-1.1 4.6-2.7 6.3-1.7 1.8-4.1 2.7-7.1 2.7-.9 0-2.1-.2-3.6-.6-.7-.2-1.4-.6-2.2-1-.8-.4-1.5-1-2.2-1.7-.7-.9-1.4-2.1-2-3.6-.6-1.5-.9-3.5-.9-6.1 0-2.6.4-4.8 1.1-6.6.7-1.7 1.6-3.1 2.7-4.2 1.1-1 2.3-1.8 3.6-2.2 1.3-.4 2.5-.6 3.7-.6h1.6c.6.1 1.3.2 1.9.4.7.2 1.4.5 2.1 1 .7.4 1.3 1 1.8 1.7.9 1.1 1.4 2.1 1.7 3.1.2 1 .3 1.8.3 2.6h-4.7zM973.6 61.7h4.3v-5.2l4.5-1.5v6.8h5.4v3.4h-5.4v15.1c0 .3 0 .6.1 1 0 .4.1.7.4 1.1.2.4.5.6 1 .8.4.3 1 .4 1.8.4 1 0 1.7-.1 2.2-.2V87c-.9.2-2.1.3-3.8.3-2.1 0-3.6-.4-4.6-1.2-1-.8-1.5-2.2-1.5-4.2V65.1h-4.3v-3.4zM993.5 50.9h5.5V56h-5.5v-5.1m.5 10.9h4.6v25.1H994V61.8zM1006.1 74.7c0-1.6.2-3.2.6-4.8.4-1.6 1.1-3 2-4.4 1-1.3 2.2-2.4 3.8-3.2 1.6-.8 3.6-1.2 5.9-1.2 2.4 0 4.5.4 6.1 1.3 1.5.9 2.7 2 3.6 3.3.9 1.3 1.5 2.8 1.8 4.3.2.8.3 1.5.4 2.2v2.2c0 3.7-1 6.9-3 9.5-2 2.6-5.1 4-9.3 4-4-.1-7-1.4-9-3.9-1.9-2.5-2.9-5.6-2.9-9.3m4.7-.3c0 2.7.6 5 1.8 6.9 1.2 2 3 3 5.6 3.1.9 0 1.8-.2 2.7-.5.8-.3 1.6-.9 2.3-1.7.7-.8 1.3-1.9 1.8-3.2.4-1.3.6-2.9.6-4.7-.1-6.4-2.5-9.6-7.1-9.6-.7 0-1.5.1-2.4.3-.8.3-1.7.8-2.5 1.6-.8.7-1.4 1.7-1.9 3-.6 1.1-.9 2.8-.9 4.8zM1038.6 64.7l-.1-2.9h4.6v4.1c.2-.3.4-.8.7-1.2.3-.5.8-1 1.3-1.5.6-.5 1.4-1 2.3-1.3.9-.3 2-.5 3.4-.5.6 0 1.4.1 2.4.2.9.2 1.9.5 2.9 1.1 1 .6 1.8 1.4 2.5 2.5.6 1.2 1 2.7 1 4.7V87h-4.6V71c0-.9-.1-1.7-.2-2.4-.2-.7-.5-1.3-1.1-1.9-1.2-1.1-2.6-1.7-4.3-1.7-1.7 0-3.1.6-4.3 1.8-1.3 1.2-2 3.1-2 5.7V87h-4.6V64.7zM479.1 100.8h5.2l14.1 36.1h-5.3l-3.8-9.4h-16.2l-3.8 9.4h-5l14.8-36.1m-4.4 22.7H488l-6.5-17.8-6.8 17.8zM508.7 138.8c.1.7.2 1.4.4 1.9.2.6.5 1.1.9 1.6.8.9 2.3 1.4 4.4 1.5 1.6 0 2.8-.3 3.7-.9.9-.6 1.5-1.4 1.9-2.4.4-1.1.6-2.3.7-3.7.1-1.4.1-2.9.1-4.6-.5.9-1.1 1.7-1.8 2.3-.7.6-1.5 1-2.3 1.3-1.7.4-3 .6-3.9.6-1.2 0-2.4-.2-3.8-.6-1.4-.4-2.6-1.2-3.7-2.5-1-1.3-1.7-2.8-2.1-4.4-.4-1.6-.6-3.2-.6-4.8 0-4.3 1.1-7.4 3.2-9.5 2-2.1 4.6-3.1 7.6-3.1 1.3 0 2.3.1 3.2.4.9.3 1.6.6 2.1 1 .6.4 1.1.8 1.5 1.2l.9 1.2v-3.4h4.4l-.1 4.5v15.7c0 2.9-.1 5.2-.2 6.7-.2 1.6-.5 2.8-1 3.7-1.1 1.9-2.6 3.2-4.6 3.7-1.9.6-3.8.8-5.6.8-2.4 0-4.3-.3-5.6-.8-1.4-.5-2.4-1.2-3-2-.6-.8-1-1.7-1.2-2.7-.2-.9-.3-1.8-.4-2.7h4.9m5.3-5.8c1.4 0 2.5-.2 3.3-.7.8-.5 1.5-1.1 2-1.8.5-.6.9-1.4 1.2-2.5.3-1 .4-2.6.4-4.8 0-1.6-.2-2.9-.4-3.9-.3-1-.8-1.8-1.4-2.4-1.3-1.4-3-2.2-5.2-2.2-1.4 0-2.5.3-3.4 1-.9.7-1.6 1.5-2 2.4-.4 1-.7 2-.9 3-.2 1-.2 2-.2 2.8 0 1 .1 1.9.3 2.9.2 1.1.5 2.1 1 3 .5.9 1.2 1.6 2 2.2.8.7 1.9 1 3.3 1zM537.6 125.2c-.1 2.6.5 4.8 1.7 6.5 1.1 1.7 2.9 2.6 5.3 2.6 1.5 0 2.8-.4 3.9-1.3 1-.8 1.6-2.2 1.8-4h4.6c0 .6-.2 1.4-.4 2.3-.3 1-.8 2-1.7 3-.2.3-.6.6-1 1-.5.4-1 .7-1.7 1.1-.7.4-1.5.6-2.4.8-.9.3-2 .4-3.3.4-7.6-.2-11.3-4.5-11.3-12.9 0-2.5.3-4.8 1-6.8s2-3.7 3.8-5.1c1.2-.8 2.4-1.3 3.7-1.6 1.3-.2 2.2-.3 3-.3 2.7 0 4.8.6 6.3 1.6s2.5 2.3 3.1 3.9c.6 1.5 1 3.1 1.1 4.6.1 1.6.1 2.9 0 4h-17.5m12.9-3v-1.1c0-.4 0-.8-.1-1.2-.1-.9-.4-1.7-.8-2.5s-1-1.5-1.8-2.1c-.9-.5-2-.8-3.4-.8-.8 0-1.5.1-2.3.3-.8.2-1.5.7-2.2 1.3-.7.6-1.2 1.3-1.6 2.3-.4 1-.7 2.2-.8 3.7h13zM562.9 114.7l-.1-2.9h4.6v4.1c.2-.3.4-.8.7-1.2.3-.5.8-1 1.3-1.5.6-.5 1.4-1 2.3-1.3.9-.3 2-.5 3.4-.5.6 0 1.4.1 2.4.2.9.2 1.9.5 2.9 1.1 1 .6 1.8 1.4 2.5 2.5.6 1.2 1 2.7 1 4.7V137h-4.6v-16c0-.9-.1-1.7-.2-2.4-.2-.7-.5-1.3-1.1-1.9-1.2-1.1-2.6-1.7-4.3-1.7-1.7 0-3.1.6-4.3 1.8-1.3 1.2-2 3.1-2 5.7V137h-4.6v-22.3zM607 119.8c0-.3 0-.8-.1-1.4-.1-.6-.3-1.1-.6-1.8-.2-.6-.7-1.2-1.4-1.6-.7-.4-1.6-.6-2.7-.6-1.5 0-2.7.4-3.5 1.2-.9.8-1.5 1.7-1.9 2.8-.4 1.1-.6 2.2-.7 3.2-.1 1.1-.2 1.8-.1 2.4 0 1.3.1 2.5.3 3.7.2 1.2.5 2.3.9 3.3.8 2 2.4 3 4.8 3.1 1.9 0 3.3-.7 4.1-1.9.8-1.1 1.2-2.3 1.2-3.6h4.6c-.2 2.5-1.1 4.6-2.7 6.3-1.7 1.8-4.1 2.7-7.1 2.7-.9 0-2.1-.2-3.6-.6-.7-.2-1.4-.6-2.2-1-.8-.4-1.5-1-2.2-1.7-.7-.9-1.4-2.1-2-3.6-.6-1.5-.9-3.5-.9-6.1 0-2.6.4-4.8 1.1-6.6.7-1.7 1.6-3.1 2.7-4.2 1.1-1 2.3-1.8 3.6-2.2 1.3-.4 2.5-.6 3.7-.6h1.6c.6.1 1.3.2 1.9.4.7.2 1.4.5 2.1 1 .7.4 1.3 1 1.8 1.7.9 1.1 1.4 2.1 1.7 3.1.2 1 .3 1.8.3 2.6H607zM629.1 137.1l-3.4 9.3H621l3.8-9.6-10.3-25h5.2l7.6 19.8 7.7-19.8h5z"/> </svg> </span> </a> <button class="usa-menu-btn usa-button l-header__menu-button">Menu</button> </div> <div class="l-header__search"> <form class="usa-search usa-search--small usa-search--epa" method="get" action="https://web.archive.org/web/20211028015312/https://search.epa.gov/epasearch"> <div role="search"> <label class="usa-sr-only" for="search-box">Search</label> <input class="usa-input" id="search-box" type="search" name="querytext" placeholder="Search EPA.gov"> <button class="usa-button" type="submit"> <span class="usa-sr-only">Search</span> </button> <input type="hidden" name="areaname" value=""> <input type="hidden" name="areacontacts" value=""> <input type="hidden" name="areasearchurl" value=""> <input type="hidden" name="typeofsearch" value="epa"> <input type="hidden" name="result_template" value=""> </div> </form> </div> </div> </div> <div class="l-header__nav"> <nav class="usa-nav usa-nav--epa" role="navigation" aria-label="Primary navigation"> <div class="usa-nav__inner"> <button class="usa-nav__close" aria-label="Close"> <svg class="icon icon--nav-close" aria-hidden="true" role="img"><title>Primary navigation</title><use xlink:href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/sprite.artifact.svg#close"></use></svg> </button> <div class="usa-nav__menu"> <ul class="menu menu--main"> <li class="menu__item has-subnav is-expanded"><button class="menu__link has-subnav is-expanded usa-nav__link" aria-expanded="false"> Environmental Topics </button><ul class="menu menu__subnav"><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/environmental-topics" class="menu__link" data-drupal-link-system-path="node/164839">Environmental Topics</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/environmental-topics/air-topics" class="menu__link" data-drupal-link-system-path="node/165225">Air</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/bedbugs" class="menu__link" data-drupal-link-system-path="node/17591">Bed Bugs</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/environmental-topics/chemicals-and-toxics-topics" class="menu__link" data-drupal-link-system-path="node/165371">Chemicals and Toxics</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/climate-change" class="menu__link" data-drupal-link-system-path="node/37925">Climate Change</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/emergency-response" class="menu__link" data-drupal-link-system-path="node/18839">Emergency Response</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/environmental-topics/location-specific-environmental-information" class="menu__link" data-drupal-link-system-path="node/165443">Environmental Information by Location </a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/environmental-topics/greener-living" class="menu__link" data-drupal-link-system-path="node/165399">Greener Living</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/environmental-topics/health-topics" class="menu__link" data-drupal-link-system-path="node/165317">Health</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/environmental-topics/land-waste-and-cleanup-topics" class="menu__link" data-drupal-link-system-path="node/165171">Land, Waste, and Cleanup</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/lead" class="menu__link" data-drupal-link-system-path="node/3085">Lead</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/mold" class="menu__link" data-drupal-link-system-path="node/37083">Mold</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/pesticides" class="menu__link" data-drupal-link-system-path="node/107939">Pesticides</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/radon" class="menu__link" data-drupal-link-system-path="node/38609">Radon</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/environmental-topics/science-topics" class="menu__link" data-drupal-link-system-path="node/172685">Science Topics</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/environmental-topics/water-topics" class="menu__link" data-drupal-link-system-path="node/164827">Water Topics</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/topics-epa-web" class="menu__link" data-drupal-link-system-path="topics-epa-web">A-Z Topic Index</a></li></ul></li> <li class="menu__item has-subnav is-expanded"><button class="menu__link has-subnav is-expanded usa-nav__link" aria-expanded="false"> Laws & Regulations </button><ul class="menu menu__subnav"><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/laws-regulations" title="View links to regulatory information by topic and sector, and to top pages about environmental laws, regulations, policies, compliance, and enforcement" class="menu__link" data-drupal-link-system-path="node/3157">Laws & Regulations</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/regulatory-information-sector" class="menu__link" data-drupal-link-system-path="node/3173">By Business Sector</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/regulatory-information-topic" class="menu__link" data-drupal-link-system-path="node/66677">By Topic</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/compliance" class="menu__link" data-drupal-link-system-path="node/19411">Compliance</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/enforcement" class="menu__link" data-drupal-link-system-path="node/10885">Enforcement</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/guidance" class="menu__link" data-drupal-link-system-path="node/237295">Guidance</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/laws-regulations/laws-and-executive-orders" class="menu__link" data-drupal-link-system-path="node/66719">Laws and Executive Orders</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/laws-regulations/regulations" class="menu__link" data-drupal-link-system-path="node/11249">Regulations</a></li></ul></li> <li class="menu__item has-subnav is-expanded"><button class="menu__link has-subnav is-expanded usa-nav__link" aria-expanded="false"> Report a Violation </button><ul class="menu menu__subnav"><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/report-violation" class="menu__link" data-drupal-link-system-path="node/271510">Report a Violation</a></li><li class="menu__item"><a href="https://web.archive.org/web/20211028015312/https://echo.epa.gov/report-environmental-violations" class="menu__link">Environmental Violations</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/office-inspector-general/forms/epa-oig-hotline-complaint-form" class="menu__link" data-drupal-link-system-path="node/267103">Fraud, Waste or Abuse</a></li></ul></li> <li class="menu__item has-subnav is-expanded"><button class="menu__link has-subnav is-expanded usa-nav__link" aria-expanded="false"> About EPA </button><ul class="menu menu__subnav"><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/aboutepa" class="menu__link" data-drupal-link-system-path="node/851">About EPA</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/aboutepa/epa-organization-chart" class="menu__link" data-drupal-link-system-path="node/2481">Organization Chart</a></li><li class="menu__item"><a href="https://web.archive.org/web/20211028015312/https://cfpub.epa.gov/locator/index.cfm" class="menu__link">Staff Directory</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/planandbudget" class="menu__link" data-drupal-link-system-path="node/863">Planning, Budget, and Results</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/careers" class="menu__link" data-drupal-link-system-path="node/32663">Jobs and Internships</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/aboutepa" class="menu__link" data-drupal-link-system-path="node/851">Headquarters Offices</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/aboutepa/regional-and-geographic-offices" class="menu__link" data-drupal-link-system-path="node/254965">Regional Offices</a></li><li class="menu__item"><a href="/web/20211028015312/https://www.epa.gov/aboutepa/research-centers-programs-and-science-advisory-organizations" class="menu__link" data-drupal-link-system-path="node/254969">Lab and Research Centers</a></li></ul></li> </ul> </div> </div> </nav> </div> </header> <main id="main" class="main" role="main" tabindex="-1"> <div class="l-page has-footer"> <div class="l-constrain"> <div class="l-page__header"> <div class="l-page__header-first"> <div class="web-area-title">Underground Injection Control (UIC)</div> </div> <div class="l-page__header-last"> <a href="/web/20211028015312/https://www.epa.gov/uic/forms/contact-us-about-underground-injection-control" class="header-link">Contact Us</a> </div> </div> <div class="l-sidebar l-sidebar--reversed"> <div class="l-sidebar__main"> <article role="article" class="article" lang="en"> <h1 class="page-title"> Class II Oil and Gas Related Injection Wells </h1> <div data-drupal-messages-fallback class="hidden"></div> <div class="l-sidebar"> <div class="l-sidebar__main"> <p>On this page:</p><ul> <li><a href="#well_use">Use of Class II wells</a></li> <li><a href="#well_types">Class II well types</a></li> <li><a href="#dw_protect">Protecting drinking water resources</a></li> <li><a href="#well_reqs">Class II well requirements</a> <ul> <li><a href="#ClassII"><ins data-date="2019,8,26">Class II direct implementation permitting, transparency, and efficiency</ins></a></li> </ul> </li> <li><a href="#dfhf">Diesel fuels hydraulic fracturing</a></li> <li><a href="#addit_info">Additional information</a></li> </ul><hr/><h2><a id="well_use" name="well_use"></a>Use of Class II wells</h2><p>Class II wells are used only to inject fluids associated with oil and natural gas production. Class II fluids are primarily brines (salt water) that are brought to the surface while producing oil and gas. It is estimated that over 2 billion gallons of fluids are injected in the United States every day. Most oil and gas injection wells are in Texas, California, Oklahoma, and Kansas.</p><p>The number of Class II wells varies from year to year based on fluctuations in oil and gas demand and production. Approximately 180,000 Class II wells are in operation in the United States. </p><p>Class II wells fall into one of three categories.</p><ul> <li>Disposal wells</li> <li>Enhanced recovery wells</li> <li>Hydrocarbon storage wells</li> </ul><hr/><h2><a id="well_types" name="well_types"></a>Class II well types</h2><h3>Disposal wells</h3><p>During oil and gas extraction, brines are also brought to the surface. Brines are separated from hydrocarbons at the surface and reinjected into the same or similar underground formations for disposal. Wastewater from hydraulic fracturing activities can also be injected into Class II wells.</p><p>Class II disposal wells make up about 20 percent of the total number of Class II wells.</p><h3>Enhanced recovery wells</h3><p>Fluids consisting of brine, freshwater, steam, polymers, or carbon dioxide are injected into oil-bearing formations to recover residual oil and in limited applications, natural gas.</p><p>The injected fluids thin (decrease the viscosity) or displace small amounts of extractable oil and gas. Oil and gas is then available for recovery. In a typical configuration, a single injection well is surrounded by multiple production wells that bring oil and gas to the surface.</p><p>The UIC program does not regulate wells that are solely used for production. However, EPA does have authority to regulate <span class="definition js-definition"><button class="definition__trigger js-definition__trigger">hydraulic fracturing</button><span class="definition__tooltip js-definition__tooltip" role="tooltip"><dfn class="definition__term">hydraulic fracturing</dfn>The process of using high pressure to pump sand along with water and other fluids into subsurface rock formations in order to improve flow of oil and gas into a wellbore.</span></span> when diesel fuels are used in fluids or propping agents. During hydraulic fracturing, another enhanced recovery process, a viscous fluid is injected under high pressure until the desired fracturing is achieved, followed by a proppant such as sand. The pressure is then released and the proppant holds the fractures open to allow fluid to return to the well.</p><p>Enhanced recovery wells are the most numerous type of Class II wells. They represent as much as 80 percent of the total number of Class II wells.</p><h3>Hydrocarbon storage wells </h3><p>Liquid hydrocarbons are injected into underground formations (such as salt caverns) where they are stored, generally, as part of the U.S. Strategic Petroleum Reserve.</p><p>Over 100 liquid hydrocarbon storage wells operate in the United States.</p><hr/><h2><a id="dw_protect" name="dw_protect"></a>Protecting drinking water resources </h2><p>Extraction of oil and gas usually produces large amounts of brine. Often saltier than seawater, this brine can contain toxic metals and radioactive substances. Brines can damage the environment and public health if discharged to water or land. Deep underground injection of brines in formations isolated from underground sources of drinking water prevents soil and water contamination.</p><p>When states began to implement rules preventing disposal of brine to surface water bodies and soils, injection became the preferred way to dispose of this waste fluid. All oil and gas producing states require the injection of brine into the originating formation or similar formations. </p><hr/><h2><a id="well_reqs" name="well_reqs"></a>Class II well requirements</h2><p>States (including federally recognized tribes and U.S. territories) have the option of requesting primacy for Class II wells under either Section 1422 or 1425 of the SDWA.</p><p>Under Section 1422 states must meet EPA’s minimum requirements for UIC programs. Programs authorized under section 1422 must include well owner and operator requirements for:</p><ul> <li>Construction</li> <li>Operation</li> <li>Monitoring and testing</li> <li>Reporting</li> <li>Closure requirements </li> </ul><p>Under Section 1422 enhanced recovery wells may either be issued permits or be authorized by rule. Disposal wells are issued permits. The owners or operators of the wells must meet all applicable requirements, including strict construction and conversion standards and regular testing and inspection.</p><p>Under Section 1425 states must demonstrate that their existing standards are effective in preventing endangerment of USDWs. These programs must include requirements for:</p><ul> <li>Permitting</li> <li>Inspections</li> <li>Monitoring</li> <li>Record-keeping </li> <li>Reporting</li> </ul><h3><a id="ClassII" name="ClassII"></a>Class II direct implementation permitting, transparency, and efficiency</h3><p>EPA’s UIC Program is taking steps to improve efficiency and transparency in permitting of Class II permits issued by the EPA (direct implementation). In support of this effort, EPA developed a document to clearly communicate the approach EPA takes when conducting a completeness review of Class II permit applications received by EPA.</p><p><a href="/web/20211028015312/https://www.epa.gov/uic/uic-class-ii-permit-application-completeness-review-checklist">Review EPA's completeness review checklist.</a></p><hr/><h2><a id="dfhf" name="dfhf"></a>Diesel fuels hydraulic fracturing</h2><p>Oil and gas producers use hydraulic fracturing to stimulate wells and recover oil and natural gas from geologic formations. Source rocks include:</p><ul> <li>Coalbeds</li> <li>Shales</li> <li>Tight sandstones</li> </ul><p>Source rocks are fractured by fluids injected under high pressure. The fractures allow oil and gas to flow to production wells.</p><p>In the Energy Policy Act of 2005, Congress created a broad exemption for hydraulic fracturing under the SDWA. Specifically, hydraulic fracturing – except when using diesel fuel – is excluded from the definition of underground injection and is not subject to regulation under the UIC program (SDWA Section 1421(d)(1)(B)). </p><p>In 2014 EPA released information clarifying UIC program requirements for underground injection of diesel fuels in hydraulic fracturing. The Agency also released guidance for EPA permit writers implementing UIC Class II requirements.</p><p>The EPA has developed the information and guidance to:</p><ul> <li>Explain that owners or operators must obtain a UIC Class II permit before injecting diesel fuels for hydraulic fracturing</li> <li>Explain EPA's interpretation of the SDWA term “diesel fuels” for permitting purposes</li> <li>Describe existing UIC Class II program requirements for permitting underground injection of diesel fuels in hydraulic fracturing</li> <li>Provide guidance for EPA’s permit writers preparing UIC Class II permits for diesel fuels use in hydraulic fracturing</li> </ul><p><a href="/web/20211028015312/https://www.epa.gov/uic/diesel-fuels-hydraulic-fracturing-dfhf">Read EPA's revised guidance for diesel fuels hydraulic fracturing and related documents.</a></p><hr/><h2><a id="addit_info" name="addit_info"></a>Additional information</h2><p><a href="/web/20211028015312/https://www.epa.gov/uic/underground-injection-control-regulations-and-safe-drinking-water-act-provisions">Visit the regulations page to read more about the requirements for owners and operators of Class II wells.</a></p> </div> <div class="l-sidebar__sidebar"> <div class="box box--related-info"> <h2 class="box__title"> Learn More </h2> <div class="box__content"> <p><a href="/web/20211028015312/https://www.epa.gov/uic/diesel-fuels-hydraulic-fracturing-dfhf">Guidance for diesel fuels hydraulic fracturing</a></p> <p><a href="/web/20211028015312/https://www.epa.gov/uic/primary-enforcement-authority-underground-injection-control-program">Primary enforcement authority</a></p> <p><a href="/web/20211028015312/https://www.epa.gov/uic/compliance-reporting-requirements-injection-well-owners-and-operators-and-state-regulatory">Compliance requirements for injection well owners or operators and UIC state programs</a></p> </div> </div> <div class="box"> <h2 class="box__title"> Cross-sectional diagram showing UIC Class II wells </h2> <div class="box__content"> <p> <figure class="figure figure--original"> <div class="figure__media"> <img src="/web/20211028015312im_/https://www.epa.gov/sites/default/files/2015-06/class2wells__0.jpg" width="180" height="662" alt="Cross Sectional drawing of Class II Well Types" loading="lazy"/> </div> <figcaption class="figure__caption">Class II wells are used to inject fluids associated with oil and gas production. Injection of fluids is typically thousands of feet below the surface into rock formations isolated from underground sources of drinking water.</figcaption> </figure> </p> </div> </div> </div> </div> </article> </div> <div class="l-sidebar__sidebar"> <ul class="menu--sidenav menu menu--group_menu_link_content-356"> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/uic" title="Underground Injection Control Home" class="menu-node-unpublished menu__link" data-drupal-link-system-path="node/74855">Underground Injection Control Home</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/uic/class-i-industrial-and-municipal-waste-disposal-wells" title="Class I UIC Injection Wells" class="menu-node-unpublished menu__link" data-drupal-link-system-path="node/78885">Class I Industrial and Municipal Waste Disposal Wells</a> </li> <li class="menu__item is-active-trail"> <a href="/web/20211028015312/https://www.epa.gov/uic/class-ii-oil-and-gas-related-injection-wells" title="Class II UIC Injection Wells" class="menu-node-unpublished menu__link is-active-trail is-active" data-drupal-link-system-path="node/78919">Class II Oil and Gas Related Injection Wells</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/uic/class-iii-injection-wells-solution-mining" title="Class III UIC Injection Wells" class="menu-node-unpublished menu__link" data-drupal-link-system-path="node/79055">Class III Injection Wells for Solution Mining</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/uic/class-iv-shallow-hazardous-and-radioactive-injection-wells" title="Class IV UIC Injection Wells" class="menu-node-unpublished menu__link" data-drupal-link-system-path="node/79143">Class IV Shallow Hazardous and Radioactive Injection Wells</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/uic/class-v-wells-injection-non-hazardous-fluids-or-above-underground-sources-drinking-water" title="UIC Class V Wells" class="menu-node-unpublished menu__link" data-drupal-link-system-path="node/83985">Class V Wells for Injection of Non-Hazardous Fluids into or Above Underground Sources of Drinking Water</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/uic/class-vi-wells-used-geologic-sequestration-co2" title="UIC Class VI Injection Wells" class="menu-node-unpublished menu__link" data-drupal-link-system-path="node/83981">Class VI Wells Used for Geologic Sequestration of CO2</a> </li> </ul> </div> </div> </div> <div class="l-page__footer"> <div class="l-constrain"> <a href="/web/20211028015312/https://www.epa.gov/uic/forms/contact-us-about-underground-injection-control">Contact Us</a> to ask a question, provide feedback, or report a problem. </div> </div> </div> </main> <footer class="footer" role="contentinfo"> <div class="l-constrain"> <img class="footer__epa-seal" src="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/epa-seal.svg" alt="United States Environmental Protection Agency" height="100" width="100"> <div class="footer__content contextual-region"> <div class="footer__column"> <h2>Discover.</h2> <ul class="menu menu--footer"> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/accessibility" class="menu__link">Accessibility</a> </li>  <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/planandbudget" class="menu__link">Budget & Performance</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/contracts" class="menu__link">Contracting</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/home/wwwepagov-snapshots" class="menu__link">EPA www Web Snapshot</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/grants" class="menu__link">Grants</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/ocr/whistleblower-protections-epa-and-how-they-relate-non-disclosure-agreements-signed-epa-employees" class="menu__link">No FEAR Act Data</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/web-policies-and-procedures/plain-writing" class="menu__link">Plain Writing</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/privacy" class="menu__link">Privacy</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/privacy/privacy-and-security-notice" class="menu__link">Privacy and Security Notice</a> </li> </ul> </div> <div class="footer__column"> <h2>Connect.</h2> <ul class="menu menu--footer"> <li class="menu__item"> <a href="https://web.archive.org/web/20211028015312/https://www.data.gov/" class="menu__link">Data.gov</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/office-inspector-general/about-epas-office-inspector-general" class="menu__link">Inspector General</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/careers" class="menu__link">Jobs</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/newsroom" class="menu__link">Newsroom</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/data" class="menu__link">Open Government</a> </li> <li class="menu__item"> <a href="https://web.archive.org/web/20211028015312/https://www.regulations.gov/" class="menu__link">Regulations.gov</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/newsroom/email-subscriptions-epa-news-releases" class="menu__link">Subscribe</a> </li> <li class="menu__item"> <a href="https://web.archive.org/web/20211028015312/https://www.usa.gov/" class="menu__link">USA.gov</a> </li> <li class="menu__item"> <a href="https://web.archive.org/web/20211028015312/https://www.whitehouse.gov/" class="menu__link">White House</a> </li> </ul> </div> <div class="footer__column"> <h2>Ask.</h2> <ul class="menu menu--footer"> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/home/forms/contact-epa" class="menu__link">Contact EPA</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/web-policies-and-procedures/epa-disclaimers" class="menu__link">EPA Disclaimers</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/home/epa-hotlines" class="menu__link">Hotlines</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/foia" class="menu__link">FOIA Requests</a> </li> <li class="menu__item"> <a href="/web/20211028015312/https://www.epa.gov/home/frequent-questions-specific-epa-programstopics" class="menu__link">Frequent Questions</a> </li> </ul> <h2>Follow.</h2> <ul class="menu menu--social"> <li class="menu__item"> <a class="menu__link" aria-label="EPA’s Facebook" href="https://web.archive.org/web/20211028015312/https://www.facebook.com/EPA"> <svg class="icon icon--social" aria-hidden="true"> <use xlink:href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/sprite.artifact.svg#facebook-square"></use> </svg> </a> </li> <li class="menu__item"> <a class="menu__link" aria-label="EPA’s Twitter" href="https://web.archive.org/web/20211028015312/https://twitter.com/epa"> <svg class="icon icon--social" aria-hidden="true"> <use xlink:href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/sprite.artifact.svg#twitter-square"></use> </svg> </a> </li> <li class="menu__item"> <a class="menu__link" aria-label="EPA’s Youtube" href="https://web.archive.org/web/20211028015312/https://www.youtube.com/user/USEPAgov"> <svg class="icon icon--social" aria-hidden="true"> <use xlink:href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/sprite.artifact.svg#youtube-square"></use> </svg> </a> </li> <li class="menu__item"> <a class="menu__link" aria-label="EPA’s Flickr" href="https://web.archive.org/web/20211028015312/https://www.flickr.com/photos/usepagov"> <svg class="icon icon--social" aria-hidden="true"> <use xlink:href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/sprite.artifact.svg#flickr-square"></use> </svg> </a> </li> <li class="menu__item"> <a class="menu__link" aria-label="EPA’s Instagram" href="https://web.archive.org/web/20211028015312/https://www.instagram.com/epagov"> <svg class="icon icon--social" aria-hidden="true"> <use xlink:href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/sprite.artifact.svg#instagram-square"></use> </svg> </a> </li> </ul> <p class="footer__last-updated">Last updated on September 14, 2021</p> </div> </div> </div> </footer> </div> <a href="#top" class="back-to-top" title="Back to top" aria-hidden="true"> <svg class="back-to-top__icon" role="img" aria-label="Back to top"> <use xlink:href="/web/20211028015312im_/https://www.epa.gov/themes/epa_theme/images/sprite.artifact.svg#arrow"></use> </svg> </a> <script type="application/json" data-drupal-selector="drupal-settings-json">{"path":{"baseUrl":"\/","scriptPath":null,"pathPrefix":"","currentPath":"node\/78919","currentPathIsAdmin":false,"isFront":false,"currentLanguage":"en"},"pluralDelimiter":"\u0003","suppressDeprecationErrors":true,"ajaxPageState":{"libraries":"epa_alerts\/epaAlerts,epa_theme\/global,epa_theme\/media_link,epa_wysiwyg\/epa-new,filter\/caption,media\/filter.caption,paragraphs\/drupal.paragraphs.unpublished,system\/base","theme":"epa_theme","theme_token":null},"ajaxTrustedUrl":[],"ckeditorheight":{"offset":1,"line_height":1.5,"unit":"em","disable_autogrow":false},"viewsAjaxGet":{"public_alerts":"public_alerts"},"epaAlerts":{"context":"public"},"mediaelement":{"attachSitewide":0},"user":{"uid":0,"permissionsHash":"311ea3f006616a03837cc49d8d77fce78a026f631684dc73097b2a112680a6c5"}}</script> <script src="/web/20211028015312js_/https://www.epa.gov/core/assets/vendor/jquery/jquery.min.js?v=3.6.0"></script> <script src="/web/20211028015312js_/https://www.epa.gov/core/assets/vendor/css-escape/css.escape.js?v=1.5.1"></script> <script src="/web/20211028015312js_/https://www.epa.gov/core/assets/vendor/jquery-once/jquery.once.min.js?v=2.2.3"></script> <script src="/web/20211028015312js_/https://www.epa.gov/core/misc/drupalSettingsLoader.js?v=9.2.6"></script> <script src="/web/20211028015312js_/https://www.epa.gov/core/misc/drupal.js?v=9.2.6"></script> <script src="/web/20211028015312js_/https://www.epa.gov/core/misc/drupal.init.js?v=9.2.6"></script> <script src="/web/20211028015312js_/https://www.epa.gov/core/assets/vendor/tabbable/index.umd.min.js?v=5.2.0"></script> <script src="/web/20211028015312js_/https://www.epa.gov/modules/custom/epa_wysiwyg/js/plugins/epaNew/epaNew.js?r0y0d3"></script> <script src="/web/20211028015312js_/https://www.epa.gov/themes/epa_theme/js/dist/common.min.js?v=9.2.6"></script> <script src="/web/20211028015312js_/https://www.epa.gov/themes/epa_theme/js/dist/scripts.min.js?v=9.2.6"></script> <script src="/web/20211028015312js_/https://www.epa.gov/themes/epa_theme/js/dist/sitewide-alert.min.js?v=9.2.6"></script> <script src="/web/20211028015312js_/https://www.epa.gov/themes/epa_theme/js/dist/definition.min.js?v=9.2.6"></script> <script src="/web/20211028015312js_/https://www.epa.gov/themes/epa_theme/js/dist/external-links.min.js?v=9.2.6"></script> <script src="/web/20211028015312js_/https://www.epa.gov/themes/epa_theme/js/dist/media-link.min.js?v=9.2.6"></script> <script src="/web/20211028015312js_/https://www.epa.gov/core/assets/vendor/jquery-form/jquery.form.min.js?v=4.3.0"></script> <script src="/web/20211028015312js_/https://www.epa.gov/core/misc/progress.js?v=9.2.6"></script> <script src="/web/20211028015312js_/https://www.epa.gov/core/modules/responsive_image/js/responsive_image.ajax.js?v=9.2.6"></script> <script src="/web/20211028015312js_/https://www.epa.gov/core/misc/ajax.js?v=9.2.6"></script> <script src="/web/20211028015312js_/https://www.epa.gov/core/themes/stable/js/ajax.js?v=9.2.6"></script> <script src="/web/20211028015312js_/https://www.epa.gov/modules/contrib/views_ajax_get/views_ajax_get.js?r0y0d3"></script> <script src="/web/20211028015312js_/https://www.epa.gov/modules/custom/epa_alerts/js/epaAlerts.js?r0y0d3" defer async></script> <script type="text/javascript">window.NREUM||(NREUM={});NREUM.info={"beacon":"bam.nr-data.net","licenseKey":"ead36e43ac","applicationID":"529886857,529885622","transactionName":"MwRbbRdWDUUHVkdaWgpOeFoRXgxYSUVSVFA7AlhaDVI=","queueTime":0,"applicationTime":86,"atts":"H0NYG19MHks=","errorBeacon":"bam.nr-data.net","agent":""}</script></body> </html>