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dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Limit for exposure to a chemical substance</div> <style data-mw-deduplicate="TemplateStyles:r1251242444">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px 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class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/50px-Question_book-new.svg.png" decoding="async" width="50" height="39" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/75px-Question_book-new.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/100px-Question_book-new.svg.png 2x" data-file-width="512" data-file-height="399" /></a></span></div></td><td class="mbox-text"><div class="mbox-text-span">This article <b>needs additional citations for <a href="/wiki/Wikipedia:Verifiability" title="Wikipedia:Verifiability">verification</a></b>.<span class="hide-when-compact"> Please help <a href="/wiki/Special:EditPage/Recommended_exposure_limit" title="Special:EditPage/Recommended exposure limit">improve this article</a> by <a href="/wiki/Help:Referencing_for_beginners" title="Help:Referencing for beginners">adding citations to reliable sources</a>. Unsourced material may be challenged and removed.<br /><small><span class="plainlinks"><i>Find sources:</i> <a rel="nofollow" class="external text" href="https://www.google.com/search?as_eq=wikipedia&q=%22Recommended+exposure+limit%22">"Recommended exposure limit"</a> – <a rel="nofollow" class="external text" href="https://www.google.com/search?tbm=nws&q=%22Recommended+exposure+limit%22+-wikipedia&tbs=ar:1">news</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?&q=%22Recommended+exposure+limit%22&tbs=bkt:s&tbm=bks">newspapers</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?tbs=bks:1&q=%22Recommended+exposure+limit%22+-wikipedia">books</a> <b>·</b> <a rel="nofollow" class="external text" href="https://scholar.google.com/scholar?q=%22Recommended+exposure+limit%22">scholar</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.jstor.org/action/doBasicSearch?Query=%22Recommended+exposure+limit%22&acc=on&wc=on">JSTOR</a></span></small></span> <span class="date-container"><i>(<span class="date">June 2019</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <p>A <b>recommended exposure limit</b> (<b>REL</b>) is an <a href="/wiki/Occupational_exposure_limit" title="Occupational exposure limit">occupational exposure limit</a> that has been recommended by the <a href="/wiki/United_States" title="United States">United States</a> <a href="/wiki/National_Institute_for_Occupational_Safety_and_Health" title="National Institute for Occupational Safety and Health">National Institute for Occupational Safety and Health</a>.<sup id="cite_ref-Pocket_Guide_1-0" class="reference"><a href="#cite_note-Pocket_Guide-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> The REL is a level that NIOSH believes would be protective of worker safety and health over a working lifetime if used in combination with engineering and work practice controls, exposure and medical monitoring, posting and labeling of hazards, worker training and <a href="/wiki/Personal_protective_equipment" title="Personal protective equipment">personal protective equipment</a>. To formulate these recommendations, NIOSH evaluates all known and available medical, biological, engineering, chemical, trade, and other information. Although not legally enforceable limits, RELS are transmitted to the <a href="/wiki/Occupational_Safety_and_Health_Administration" title="Occupational Safety and Health Administration">Occupational Safety and Health Administration</a> (OSHA) or the <a href="/wiki/Mine_Safety_and_Health_Administration" title="Mine Safety and Health Administration">Mine Safety and Health Administration</a> (MSHA) of the <a href="/wiki/U.S._Department_of_Labor" class="mw-redirect" title="U.S. Department of Labor">U.S. Department of Labor</a> for use in promulgating legal standards.<sup id="cite_ref-Pocket_Guide_1-1" class="reference"><a href="#cite_note-Pocket_Guide-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> </p><p>All RELs are located in the <i>NIOSH Pocket Guide to Chemical Hazards</i>, along with other key data for 677 chemical or substance groupings. The <i>Pocket Guide</i> is a source of general industrial hygiene information for workers, employers, and occupational health professionals.<sup id="cite_ref-Pocket_Guide_1-2" class="reference"><a href="#cite_note-Pocket_Guide-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>NIOSH recommendations are also published in a variety of documents, including: </p> <ul><li>Criteria documents – These recommend workplace exposure limits and appropriate preventive measures to reduce or eliminate adverse health effects and accidental injuries.</li> <li>Current Intelligence Bulletins (CIBs) – These share new scientific information about occupational hazards, highlighting a formerly unrecognized hazard, reporting new data on a known hazard, or presenting information on hazard control.</li> <li>Alerts, Special Hazard Reviews, Occupational Hazard Assessments, and Technical Guidelines - These assess the safety and health problems associated with a given agent or hazard and recommend appropriate control and surveillance methods. Although these documents are not intended to supplant the more comprehensive criteria documents, they are prepared to assist OSHA and MSHA in the formulation of regulation.<sup id="cite_ref-Pocket_Guide_1-3" class="reference"><a href="#cite_note-Pocket_Guide-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup></li></ul> <p>In addition to these publications, NIOSH periodically presents testimony before various Congressional committees and at OSHA and MSHA rulemaking hearings.<sup id="cite_ref-Pocket_Guide_1-4" class="reference"><a href="#cite_note-Pocket_Guide-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Understanding_and_applying_NIOSH_recommended_exposure_limits">Understanding and applying NIOSH recommended exposure limits</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Recommended_exposure_limit&action=edit&section=1" title="Edit section: Understanding and applying NIOSH recommended exposure limits"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/National_Institute_for_Occupational_Safety_and_Health" title="National Institute for Occupational Safety and Health">National Institute for Occupational Safety and Health</a> (NIOSH) RELs are designed to protect the health and well-being of workers by recommending safe exposure levels. To really use these guidelines well, safety professionals need to understand the recommended exposure levels, how to measure them, and ways to make sure workers aren't exposed to harmful stuff. It's not just about knowing the numbers; it's also about checking regularly and making changes if needed to keep everyone safe. </p><p>RELs are written as <a href="/wiki/Permissible_exposure_limit" title="Permissible exposure limit">time-weighted average</a> (TWA) exposures. This TWA is calculated for a standard workday of up to 10 hours, over a 40-hour workweek. This is slightly different to <a href="/wiki/Permissible_exposure_limit" title="Permissible exposure limit">permissible exposure limit</a> (PELs), which are calculated for 8 hours over a 40-hour workweek instead.<sup id="cite_ref-Pocket_Guide_1-5" class="reference"><a href="#cite_note-Pocket_Guide-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> NIOSH recognizes that certain scenarios demand more immediate attention and has therefore introduced additional measures. Sometimes it's not always about the whole day and a worker might be around a lot of the stuff in a short burst. So, they set a <a href="/wiki/Short-term_exposure_limit" title="Short-term exposure limit">short-term exposure limit</a> (STEL), meaning the concentration of a substance that should never be exceeded within a specified 15-minute period. There is also a ceiling limit (C). This is a substance no one should be exposed to, even for a moment. These guidelines aim to strike a balance; it is to keep workers safe from harm without going overboard and making things inefficient in the workplace. The RELs, unlike permissible exposure limits or PELs set by <a href="/wiki/Occupational_Safety_and_Health_Administration" title="Occupational Safety and Health Administration">OSHA</a>, are merely guidelines -- they are not legally enforceable. An employer cannot be held liable, but they can try to implement these in the workplace. These guidelines are crucial for workplace safety. RELs undergo more frequent revisions and tend to be more stringent compared to PELs established by OSHA.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> The strictness inherent in RELs align with the latest scientific understanding and advancements in occupational health.<sup id="cite_ref-Pocket_Guide_1-6" class="reference"><a href="#cite_note-Pocket_Guide-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> This prioritizes knowledge in worker safety. </p> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Recommended_exposure_limit&action=edit&section=2" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-Pocket_Guide-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-Pocket_Guide_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Pocket_Guide_1-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Pocket_Guide_1-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-Pocket_Guide_1-3"><sup><i><b>d</b></i></sup></a> <a href="#cite_ref-Pocket_Guide_1-4"><sup><i><b>e</b></i></sup></a> <a href="#cite_ref-Pocket_Guide_1-5"><sup><i><b>f</b></i></sup></a> <a href="#cite_ref-Pocket_Guide_1-6"><sup><i><b>g</b></i></sup></a></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.cdc.gov/niosh/npg/pgintrod.html">"NIOSH Pocket Guide to Chemical Hazards"</a>. <i>NIOSH website</i><span class="reference-accessdate">. Retrieved <span class="nowrap">November 25,</span> 2019</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=NIOSH+website&rft.atitle=NIOSH+Pocket+Guide+to+Chemical+Hazards&rft_id=https%3A%2F%2Fwww.cdc.gov%2Fniosh%2Fnpg%2Fpgintrod.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ARecommended+exposure+limit" class="Z3988"></span> <span class="noviewer" typeof="mw:File"><span><img alt="Public Domain" src="//upload.wikimedia.org/wikipedia/en/thumb/6/62/PD-icon.svg/12px-PD-icon.svg.png" decoding="async" width="12" height="12" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/6/62/PD-icon.svg/18px-PD-icon.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/6/62/PD-icon.svg/24px-PD-icon.svg.png 2x" data-file-width="196" data-file-height="196" /></span></span> This article incorporates text from this source, which is in the <a href="/wiki/Public_domain" title="Public domain">public domain</a>.</span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCenters_for_Disease_Control_and_Prevention1988" class="citation journal cs1">Centers for Disease Control and Prevention (1988). <a rel="nofollow" class="external text" href="https://wonder.cdc.gov/wonder/prevguid/p0000156/p0000156.asp">"NIOSH Recommendations for Occupational Safety and Health Standards 1988"</a>. <i>MMWR</i>. <b>37</b>: 1–29.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=MMWR&rft.atitle=NIOSH+Recommendations+for+Occupational+Safety+and+Health+Standards+1988&rft.volume=37&rft.pages=1-29&rft.date=1988&rft.au=Centers+for+Disease+Control+and+Prevention&rft_id=https%3A%2F%2Fwonder.cdc.gov%2Fwonder%2Fprevguid%2Fp0000156%2Fp0000156.asp&rfr_id=info%3Asid%2Fen.wikipedia.org%3ARecommended+exposure+limit" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.sciencedirect.com/topics/medicine-and-dentistry/recommended-exposure-limit#:~:text=Recommended%20exposure%20limit%20(REL)%20is,RELs%20are%20not%20regulations">"Recommended Exposure Limit - an overview | ScienceDirect Topics"</a>. <i>www.sciencedirect.com</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2023-11-14</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.sciencedirect.com&rft.atitle=Recommended+Exposure+Limit+-+an+overview+%7C+ScienceDirect+Topics&rft_id=https%3A%2F%2Fwww.sciencedirect.com%2Ftopics%2Fmedicine-and-dentistry%2Frecommended-exposure-limit%23%3A~%3Atext%3DRecommended%2520exposure%2520limit%2520%28REL%29%2520is%2CRELs%2520are%2520not%2520regulations&rfr_id=info%3Asid%2Fen.wikipedia.org%3ARecommended+exposure+limit" class="Z3988"></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Recommended_exposure_limit&action=edit&section=3" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a rel="nofollow" class="external text" href="https://www.cdc.gov/niosh/npg/">NIOSH Pocket Guide to Chemical Hazards</a></li></ul>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Recommended_exposure_limit&oldid=1190546013">https://en.wikipedia.org/w/index.php?title=Recommended_exposure_limit&oldid=1190546013</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:National_Institute_for_Occupational_Safety_and_Health" title="Category:National Institute for Occupational Safety and Health">National Institute for Occupational Safety and Health</a></li><li><a href="/wiki/Category:Environmental_standards" title="Category:Environmental standards">Environmental standards</a></li><li><a href="/wiki/Category:Chemical_safety" title="Category:Chemical safety">Chemical safety</a></li><li><a href="/wiki/Category:Occupational_safety_and_health" title="Category:Occupational safety and health">Occupational safety and health</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:Source_attribution" title="Category:Source attribution">Source attribution</a></li><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_matches_Wikidata" title="Category:Short description matches Wikidata">Short description matches Wikidata</a></li><li><a href="/wiki/Category:Articles_needing_additional_references_from_June_2019" title="Category:Articles needing additional references from June 2019">Articles needing additional references from June 2019</a></li><li><a href="/wiki/Category:All_articles_needing_additional_references" title="Category:All articles needing additional references">All articles needing additional references</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 18 December 2023, at 14:20<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. 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