Editing Respirator (section)

== Issues ==
{{US respirator topics}}
=== Under 30 CFR 11 ===
{{further|30 CFR 11}}
In 1992, NIOSH published a draft report on the effectiveness of respirator regulations under the then-current [[30 CFR 11]]. Particulate respirators back then were mainly classified as either [[DM respirator|DM, DFM, or HEPA]].<ref>{{harvnb|NIOSH|1992}}</ref>

==== Respirator risk modelling ====
[[Respirator assigned protection factors|Assigned protection factors]] (APF) are predicated on the assumption that users are trained in the use of their respirators, and that ''100%'' of users exceed the APF.<ref>"NIOSH has concluded that APFS based on APF definitions from Myers et al. and the Guy Committee are derived from WPF data that were obtained after each test subject has been properly fitted and trained"... {{harvnb|NIOSH|1992|p=34}}</ref> This "simulated workplace protection factor" (SWPF) was said to be problematic:
{{blockquote|By inference, these data are equally at odds with the protection factors established by OSHA for various types of respirator, which were based on QNFT [quantitative fit testing] data obtained by the [[Los Alamos National Laboratory]] in the 1970s. Until recently, the SWPFs gathered during QNFT were more or less assumed to translate directly into the protection afforded by a particular respirator, or class of respirators, while worn in the workplace.{{break}}{{break}}
Apparently this is now a questionable assumption which has thrown the entire concept of fit testing into doubt.<ref name="openforum">Quote from: {{citation| title=Open Forum: Respirator Testing-Old Values |date= May 1989 |publisher=Ind. Safety and Hyg. News}}</ref>}}
The ideal assumption of ''all'' respirator users exceeding the APF is termed the ''zero control failure rate'' by NIOSH. The term ''control failure rate'' here refers to the number of respirator users, per 100 users, that fail to reach the APF.<ref name="NIOSHp52">{{harvnb|NIOSH|1992|p=52}}</ref> The risk of user error affecting the ''failure rate'', and the studies quantifying it, was, according to NIOSH, akin to the study of [[Comparison of birth control methods|contraception failure rates]].<ref>{{harvnb|NIOSH|1992|p=51}}</ref> 

This is despite there being a "reasonable expectation, of both purchasers and users, [that] ''none'' of the users will receive less protection than the class APF (when the masks are properly selected, fit tested by the employer, and properly worn by the users)". NIOSH expands on the methods for measuring this error in Chapter 7 of the draft report.<ref name="NIOSHp52" />

==== Qualitative fit testing ====
Qualitative fit testing with isoamyl acetate, irritant smoke, and saccharin were proposed as alternatives to quantitative fit testing in the 1980s, but doubts were raised as to its efficacy.<ref name="page35">{{harvnb|NIOSH|1992|pp=35-36}}</ref> 

With regards to the effectiveness of fit testing in general, others have said:<ref name="page35" /> {{blockquote|First of all, it is unfortunate that fit testing results apparently cannot be used as a reliable indication of respirator performance in the workplace. Life would be simpler if the converse were to continue to be true...{{break}}{{break}}
In my opinion, we are left with respirator fit testing, whether qualitative or quantitative, playing the role as a means of obtaining the best possible fit of a given respirator on a given person at a given time. We should not make any representation as to the ultimate efficiency in the workplace.<ref name="openforum" />}}

==== Exercise protocols ====
With regards to fit test ''protocols'', it was noted by NIOSH that "time pressures" resulted in the exclusion of intense exercises meant to simulate workplace use:<ref name="page37">{{harvnb|NIOSH|1992|p=37}}</ref> {{blockquote|Part of the original test procedure called for test subjects to be stressed by treadmill, while undergoing a quantitative respirator leak evaluation. The purpose of this stressing was to simulate actual workplace use of the respirators. We accordingly abandoned the "stress" portion of the exercises, and substituted a period to be spent in a hot humid chamber, to work up a sweat, as a substitute for physical activity.<ref>{{citation |last=Douglas |first=D. D. |title=Respirator Studies for the National Institute for Occupational Safety and Health, July 1, 1974-June 30, 1975, Los Alamos Scientific Laboratory Progress Report LA-6386-PR |publisher=Office of Scientific and Technical Information|location=Los Alamos, New Mexico |pages=35–36 |date=August 1976}}</ref>}}
Neither exercise was included in the [[OSHA]] fit test protocols. Put another way, it has been said:<ref name="page37"/> {{blockquote|The exercise time limits are very short. The required exercises are sedentary and do not replicate movements of workers that may occur in workplaces.<ref>{{citation |first=W. H. |last=Revoir |title=Comments on OSHA's Proposal to Modify Existing Provisions for Controlling Employee Exposure to Toxic Substances Found in 29 CFR 1910.1000(3) and 29 CFR 1910.134(a)(1). Comments submitted to OSHA |date=1990-05-30 |page=20}}</ref>}}

==== Noncompliance with regulation ====
In spite of the requirement to fit test by OSHA, the following observations of noncompliance with respirator regulations were made by NIOSH and OSHA:<ref name="page45">{{harvnb|NIOSH|1992|p=45-46}}</ref>
* Almost 80% of negative-pressure respirator wearers were not receiving fit testing.
* Over 70% of 123,000 manufacturing plants did not perform exposure-level monitoring, when selecting respirators to use in the plants.
* Noncompliance increased to almost 90% for the smallest plants.
* 75% of manufacturing plants did not have a written program.
* 56% of manufacturing plants did not have a professional respirator-program administrator (i.e., qualified individual supervising the program).
* Almost 50% of wearers in manufacturing plants did not receive an annual examination by a physician.
* Almost 50% of wearers in manufacturing plants did not receive respirator-use training.
* 80% of wearers in manufacturing plants did not have access to more than one facial-size mask, even though nearly all reusable masks were available in at least three sizes.<ref name="page45" />
These noncompliance errors make up what NIOSH calls the ''program protection factor'':<ref name="page47">{{harvnb|NIOSH|1992|p=47}}</ref>{{blockquote|...NIOSH has concluded that all respirator workplace studies reported in the 1980s and early 1990s are ''respirator-performance'' studies, not ''respirator program evaluation studies''. That is, they evaluate ''workplace protection factors'', not ''program protection factors''.

WPF studies frequently are conducted primarily to demonstrate "adequate protection" from a particular make and model respirator. Thus, in effect, WPF studies generally are designed and conducted to measure only respirator performance in the most favorable light possible. This is done to avoid reducing or "biasing" (i.e., systematically distorting) the observed respirator protection resulting from poorly-performed or inadequately-performed respirator program elements that are typically found in actual programs. A major objective in respirator-performance (WPF) studies is to minimize the effects of human errors, even though these errors may typically occur in actual workplace use of respirators...<ref name="page47" />
}}

==== Adherence to the regulatory minimum ====
[[File:Part 11 respirator final air-purifying APFs (1992) - illustration - page 137.jpg|alt=Table of final APFs for Part 11|thumb|Final Part 11 APFs proposed by NIOSH for air-purifying respirators, with DM respirator APFs lowered to 2.]]
APFs may be based on the filtration performance from one or two manufacturers that barely pass the regulation. When the DM and DFM respirator filter standards at the time were found to have an unacceptably high filter leakage, NIOSH proposed lowering the APF for DM respirators from 10 to 2. On this scale, 1 is a completely ineffective respirator. Some respirator manufacturers, like [[3M]], complained that DM and DFM respirators with superior filtration, that would normally receive an APF well above 2, were being "held hostage" by poorly-performing respirators.<ref>{{harvnb|NIOSH|1992|p=127}}</ref> While NIOSH acknowledged the predicament poorly-performing respirators were having on superior respirators in the same class, they concluded that the APFs, for respirator classes like DFM halfmask respirators, should be lowered to at least 6, despite APFs of 6 through 10 being allowed previously for DFM halfmasks.<ref>{{harvnb|NIOSH|1992|p=128}}</ref>

[[ANSI]] suggested additional contaminant monitoring by employers to allow for the use of DM and DFM respirators, when the [[Median aerodynamic diameter|mass median aerodynamic diameter]] of dusts in contaminated workplaces is such that DM and DFM respirators ''could work''. However, NIOSH pointed out that the poor adherence to OSHA regulations on exposure-level monitoring by employers, as well as lack of expertise in interpreting the collected data, would likely result in more workers being put at risk.<ref>{{harvnb|NIOSH|1992|pp=132-133}}</ref> In addition, NIOSH pointed out that the ANSI recommendations would effectively mandate the use of ''expensive'' Part 11 HEPA filters under Part 11 regulations,<ref>{{harvnb|NIOSH|1992|p=135}}</ref> due to lack of adherence to exposure-level monitoring rules.<ref>{{harvnb|NIOSH|1992|p=136}}</ref>

=== Hierarchy of Controls point of view under 42 CFR 84 ===
{{further|Hierarchy of hazard controls}}
[[File:NIOSH’s “Hierarchy of Controls infographic” as SVG.svg|thumb|left|Placing an overemphasis on respirator usage can neglect other, more effective ways of remedying risk, but PPE may still be necessary under certain conditions (for example, during a [[tuberculosis|TB]] outbreak)]]
The Hierarchy of Controls, noted as part of the ''Prevention Through Design'' initiative started by [[NIOSH]] with other standards bodies, is a set of guidelines emphasizing building in safety during design, as opposed to ad-hoc solutions like PPE, with multiple entities providing guidelines on how to implement safety during development<ref>{{cite web|url=https://www.cdc.gov/niosh/docs/2014-123/pdfs/2014-123_v2.pdf|title=The State of the National Initiative on Prevention through Design|date=May 2014|publisher=NIOSH|access-date=3 June 2024|archive-date=3 June 2024|archive-url=https://web.archive.org/web/20240603035524/https://www.cdc.gov/niosh/docs/2014-123/pdfs/2014-123_v2.pdf|url-status=live}}</ref> outside of NIOSH-approved respirators. US Government entities currently and formerly involved in the regulation of respirators follow the Hierarchy of Controls, including [[OSHA]]<ref name="twonine" /> and [[Mine Safety and Health Administration|MSHA]].<ref>{{cite web|url=https://www.uaf.edu/mapts/tools/15_Respiratory_Program_Requirements.pdf|title=Summary of Key MSHA Requirements for a Respiratory Protection Program|access-date=3 June 2024|archive-date=16 June 2024|archive-url=https://web.archive.org/web/20240616204739/https://www.uaf.edu/mapts/tools/15_Respiratory_Program_Requirements.pdf|url-status=live}}</ref>

However, some HOC implementations, notably MSHA's, have been criticized for allowing mining operators to skirt [[engineering controls|engineering control]] noncompliance by requiring miners to wear respirators instead if the [[permissible exposure limit]] (PEL) is exceeded, without work stoppages, breaking the hierarchy of engineering controls. Another concern was fraud related to the inability to scrutinize engineering controls,<ref>{{cite web|url=https://democrats-edworkforce.house.gov/imo/media/doc/scott_adams_comment_letter_to_dol_on_msha_proposed_silica_rule.pdf|title=RE: Lowering Miners' Exposure to Respirable Crystalline Silica and Improving Respiratory Protection (RIN 1219-AB36)|date=11 September 2023}}</ref><ref>{{cite web|url=https://www.safetyandhealthmagazine.com/articles/24515-mshas-proposed-rule-on-silica-has-shortcomings-lawmakers-say|title=MSHA's proposed rule on silica has 'shortcomings,' lawmakers say|date=21 September 2023|access-date=3 June 2024|archive-date=5 June 2024|archive-url=https://web.archive.org/web/20240605172058/https://www.safetyandhealthmagazine.com/articles/24515-mshas-proposed-rule-on-silica-has-shortcomings-lawmakers-say|url-status=live}}</ref> unlike NIOSH-approved respirators, like the [[N95 respirator|N95]], which can be fit tested by anyone, are subject to the scrutiny of NIOSH, and are [[trademark]]ed and protected under US federal law.<ref name="counterfeit">{{cite web|url=https://www.cdc.gov/niosh/npptl/usernotices/counterfeitResp.html|title=Counterfeit Respirators / Misrepresentation of NIOSH Approval|date=23 May 2024 |publisher=NIOSH}}</ref> NIOSH also noted, in a 2002 video about [[tuberculosis|TB]] respirator use, that "[[engineering controls]], like negative pressure isolation rooms may not control the TB hazard completely. The use of respirators is necessary".<ref>{{cite wikisource |title=TB Respiratory Protection - Administrators Review |publisher=NIOSH |year=2002}}</ref>

==== Respirator non-compliance ====
{{see also|N95 respirator#Later history}}
With regards to people complying with requirements to wear respirators, various papers note high respirator non-compliance across industries,<ref>{{cite journal |url=https://doi.org/10.1093/occmed/kqr132 | doi=10.1093/occmed/kqr132 | title=Factors influencing respirator use at work in respiratory patients | date=2011 | last1=Fukakusa | first1=J. | last2=Rosenblat | first2=J. | last3=Jang | first3=B. | last4=Ribeiro | first4=M. | last5=Kudla | first5=I. | last6=Tarlo | first6=S. M. | journal=Occupational Medicine | volume=61 | issue=8 | pages=576–582 | pmid=21968940 | url-access=subscription }}</ref><ref>{{cite web |url=https://doi.org/10.1093/annweh/wxae008 | doi=10.1093/annweh/wxae008 | title=Use, failure, and non-compliance of respiratory personal protective equipment and risk of upper respiratory tract infections—A longitudinal repeated measurement study during the COVID-19 pandemic among healthcare workers in Denmark | date=2024 | last1=Biering | first1=Karin | last2=Kinnerup | first2=Martin | last3=Cramer | first3=Christine | last4=Dalbøge | first4=Annett | last5=Toft Würtz | first5=Else | last6=Lund Würtz | first6=Anne Mette | last7=Kolstad | first7=Henrik Albert | last8=Schlünssen | first8=Vivi | last9=Meulengracht Flachs | first9=Esben | last10=Nielsen | first10=Kent J. | journal=Annals of Work Exposures and Health | volume=68 | issue=4 | pages=376–386 | pmid=38373246 }}</ref> with a survey noting non-compliance was due in large part due to discomfort from temperature increases along the face, and a large amount of respondents also noting the social unacceptability of provided [[N95 respirator]]s during the survey.<ref>{{cite journal |url=https://doi.org/10.1016/j.ajic.2009.09.005 | doi=10.1016/j.ajic.2009.09.005 | title=Health care workers' views about respirator use and features that should be included in the next generation of respirators | date=2010 | last1=Baig | first1=Aliya S. | last2=Knapp | first2=Caprice | last3=Eagan | first3=Aaron E. | last4=Radonovich | first4=Lewis J. | journal=American Journal of Infection Control | volume=38 | issue=1 | pages=18–25 | pmid=20036443 | pmc=7132692 }}</ref> For reasons like mishandling, ill-fitting respirators and lack of training, the Hierarchy of Controls dictates respirators be evaluated last while other controls exist and are working. Alternative controls like [[hazard elimination]], [[administrative controls]], and engineering controls like [[Ventilation (architecture)|ventilation]] are less likely to fail due to user discomfort or error.<ref>{{cite web|url=https://simplifiedsafety.com/blog/the-hierarchy-of-controls-part-four-personal-protective-equipment/|title=The Hierarchy of Controls, Part Four: Personal Protective Equipment|publisher=Simplified Safety|access-date=3 June 2024|archive-date=3 June 2024|archive-url=https://web.archive.org/web/20240603031949/https://simplifiedsafety.com/blog/the-hierarchy-of-controls-part-four-personal-protective-equipment/|url-status=live}}</ref><ref>{{cite web|url=https://www.cdc.gov/niosh/learning/safetyculturehc/module-3/7.html|title=Personal Protective Equipment (PPE): Protect the Worker with PPE|date=5 May 2023|publisher=NIOSH|access-date=3 June 2024|archive-date=3 June 2024|archive-url=https://web.archive.org/web/20240603031949/https://www.cdc.gov/niosh/learning/safetyculturehc/module-3/7.html|url-status=live}}</ref>

A U.S. Department of Labor study<ref name="Обзор-2001">{{cite book|last1=U.S. Department of Labor, Bureau of Labor Statistics|url=https://www.cdc.gov/niosh/docs/respsurv/pdfs/respsurv2001.pdf|title=Respirator Usage in Private Sector Firms, 2001|publisher=U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health|location=Morgantown, WV|pages=273|access-date=22 January 2019|archive-date=1 November 2017|archive-url=https://web.archive.org/web/20171101172745/https://www.cdc.gov/niosh/docs/respsurv/pdfs/respsurv2001.pdf|url-status=live}}</ref> showed that in almost 40 thousand American enterprises, the requirements for the correct use of respirators are not always met. Experts note that in practice it is difficult to achieve elimination of occupational morbidity with the help of respirators:

{{blockquote|It is well known how ineffective ... trying to compensate the harmful workplace conditions with ... the use of respirators by employees.<ref name="Летавет-1992">{{cite journal|author=Letavet A.A.|author-link=:ru:Летавет, Август Андреевич|date=1973|script-title=ru:Институт гигиены труда и профессиональных заболеваний в составе АМН СССР|trans-title=Research Institute of industrial hygiene and occupational diseases of AMS USSR|url=https://www.journal-irioh.ru/jour|journal=Occupational medicine and industrial ecology [Гигиена труда и профессиональные заболевания]|language=ru|pages=1–7|issn=1026-9428|number=9|access-date=22 January 2019|archive-date=23 January 2019|archive-url=https://web.archive.org/web/20190123011650/https://www.journal-irioh.ru/jour|url-status=live}}</ref>

Unfortunately, the only certain way of reducing the exceedance fraction to zero is to ensure that Co ''(note: Co - concentration of pollutants in the breathing zone)'' never exceeds the PEL value.<ref name="Nicas-1992">{{cite journal|author=M. Nicas & R. Spear|date=1992|title=A Probability Model for Assessing Exposure among Respirator Wearers: Part II - Overexposure to Chronic versus Acute Toxicants|url=https://www.tandfonline.com/toc/aiha20/53/7?nav=tocList|journal=American Industrial Hygiene Association Journal|volume=53|pages=419–426|doi=10.1080/15298669291359889|pmid=1496932|access-date=22 January 2018|number=7|archive-date=7 April 2023|archive-url=https://web.archive.org/web/20230407193829/https://www.tandfonline.com/toc/aiha20/53/7?nav=tocList|url-status=live|url-access=subscription}}</ref>}}

===== Beards =====
[[File:Facial hairstyles and filtering facepiece respirators.pdf|thumb|left|Beards can significantly affect the integrity of the respirator's face seal.]]
Certain types of facial hair can reduce fit to a significant degree. For this reason, there are facial hair guidelines for respirator users.<ref>{{cite web|url=https://blogs.cdc.gov/niosh-science-blog/2017/11/02/noshave/|title=To Beard or not to Beard? That's a good Question!|date=2 November 2017|publisher=NIOSH|access-date=27 February 2020|archive-date=18 March 2020|archive-url=https://web.archive.org/web/20200318034249/https://blogs.cdc.gov/niosh-science-blog/2017/11/02/noshave/|url-status=live}}</ref>

==== Counterfeiting, modification, and revocation of regulated respirators ====
Another disadvantage of respirators is that the onus is on the respirator user to determine if their respirator is counterfeit or has had its certification revoked.<ref name="counterfeit" /> Customers and employers can inadvertently purchase non-OEM parts for a NIOSH-approved respirator which void the NIOSH approval and violate OSHA laws, in addition to potentially compromising the fit of the respirator.<ref>{{cite web|url=https://www.osha.gov/video/respiratory-protection/niosh/transcript|title=Transcript for the OSHA Training Video Entitled Counterfeit & Altered Respirators: The Importance of Checking for NIOSH Certification|date=January 2012|publisher=US Department of Labor, OSHA|access-date=3 June 2024|archive-date=3 June 2024|archive-url=https://web.archive.org/web/20240603060828/https://www.osha.gov/video/respiratory-protection/niosh/transcript|url-status=live}}</ref>
{{Wikisource-multi|Respirator Users' Notice Use of Unapproved Subassemblies|t1=Use of Unapproved Subassemblies (1984)|Letter to All Users of Supplied-Air Respirators Use of Unapproved Supplied-Air Respirators in the Paint Spray and Automotive Refinishing Industries|t2=Use of Unapproved Supplied-Air Respirators in the Paint Spray and Automotive Refinishing Industries (1996)}}
{{Gallery
|title=Counterfeit respirator identification
|align=center
|File:Counterfeit 3M Surgical mask N95.jpg
 |A counterfeit [[N95 respirator|N95 respirator with no TC#]]
 |alt1=Counterfeit 3M respiurator
|File:3M 1860 N952020.jpg
 |Compared to the official 3M
 |alt2=3M respirator with TC#
|File:Counterfeit and Altered Respirators - The Importance of NIOSH Certification.webm
 |OSHA video on modified and counterfeit respirators
 |alt3=Video by OSHA
}}

==== Issues with fit testing ====
If respirators ''must'' be used, under 29 CFR 1910.134, OSHA requires respirator users to conduct a [[respirator fit test]], with a safety factor of 10 to offset lower fit during real world use.<ref name="twonine">{{cite web|title=MAJOR REQUIREMENTS OF OSHA'S RESPIRATORY PROTECTION STANDARD 29 CFR 1910.134|url=https://www.osha.gov/sites/default/files/training-library_major_requirements.pdf|publisher=United States Department of Labor, OSHA|access-date=3 June 2024|archive-date=27 January 2024|archive-url=https://web.archive.org/web/20240127222116/https://www.osha.gov/sites/default/files/training-library_major_requirements.pdf|url-status=live}}</ref> However, NIOSH notes the large amount of time required for fit testing has been a point of contention for employers.<ref>{{cite web|url=https://blogs.cdc.gov/niosh-science-blog/2016/01/05/fit-testing/|title=New NIOSH Study Supports the OSHA Annual Fit Testing Requirements for Filtering Facepiece Respirators|publisher=NIOSH|date=5 January 2016|first1=Ziqing|last1=Zhuang|first2=Michael|last2=Bergman|first3=Jaclyn|last3=Krah}}</ref>

Other opinions concern the change in performance of respirators in use compared to when fit testing, and compared to engineering control alternatives:

{{blockquote|The [[Respirators testing in the workplaces|very limited field tests of air-purifying respirator performance in the workplace]] show that respirators may perform far less well under actual use conditions than is indicated by laboratory [[Respirator fit test|fit factors]]. We are not yet able to predict the level of protection accurately; it will vary from person to person, and it may also vary from one use to the next for the same individual. In contrast, [[Hierarchy of hazard controls|we can predict the effectiveness of engineering controls]], and we can monitor their performance with commercially available state-of-the-art devices.<ref name="Hyatt-1984">{{cite journal|author=Edwin C. Hyatt|date=1984|title=Respirators: How well do they really protect?|url=http://www.isrp.com/|journal=Journal of the International Society for Respiratory Protection|volume=2|pages=6–19|issn=0892-6298|access-date=22 January 2018|number=1|archive-date=22 October 2016|archive-url=https://web.archive.org/web/20161022021929/http://www.isrp.com/|url-status=live}}</ref>}}

=== Issues with respirator design ===<!-- excerpted in elastomeric respirator -->
Extended or off-label use of certain negative-pressure respirators, like a [[filtering facepiece respirator]] paired with a [[surgical mask]],<ref name="npptl">"...as compared with FFRs without SM [surgical mask], higher average inhaled CO2 were observed in four of six workloads among FFRs with SM". {{cite journal |author1=E.J. Sinkule|author2=J.B. Powell|author3=F.L. Goss |title=Evaluation of N95 respirator use with a surgical mask cover: effects on breathing resistance and inhaled carbon dioxide |journal=Annals of Occupational Hygiene |date=2013 |volume=57 |issue=3 |pages=384–398 |doi=10.1093/annhyg/mes068 |pmid=23108786 |publisher=Oxford University Press |language=en |issn=2398-7308 |doi-access=free }}</ref> can result in higher levels of carbon dioxide from [[Dead space (physiology)|dead space]] and breathing resistance (pressure drop) which can impact functioning and sometimes can exceed the PEL.<ref name="npptl" /><ref name="Roberge-2010">{{cite journal |author1=R.J. Roberge|author2=A. Coca|author3=W.J. Williams|author4=J.B. Powell|author5=A.J. Palmiero |title=Physiological Impact of the N95 Filtering Facepiece Respirator on Healthcare Workers |journal=Respiratory Care |date=2010 |volume=55 |issue=5 |pages=569–577 |pmid=20420727 |url=http://rc.rcjournal.com/content/55/5/569 |publisher=American Association for Respiratory Care (AARC) |issn=0020-1324 |access-date=28 February 2021 |archive-date=31 October 2020 |archive-url=https://web.archive.org/web/20201031043804/http://rc.rcjournal.com/content/55/5/569 |url-status=live }}</ref><ref name="Смит">{{cite journal |author1=Carmen L. Smith|author2=Jane L. Whitelaw|author3=Brian Davies |title=Carbon dioxide rebreathing in respiratory protective devices: influence of speech and work rate in full-face masks |journal=Ergonomics |date=2013 |volume=56 |issue=5 |pages=781–790 |doi=10.1080/00140139.2013.777128 |pmid=23514282 |url=https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1836&context=smhpapers |publisher=Taylor & Francis |s2cid=40238982 |issn=0014-0139 |access-date=28 February 2021 |archive-date=1 November 2020 |archive-url=https://web.archive.org/web/20201101065517/https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1836&context=smhpapers |url-status=live }}</ref> This effect was significantly reduced with [[Powered air-purifying respirator|powered air purifying respirators]].<ref>{{cite journal | doi=10.1186/s12879-021-06056-0 | doi-access=free | title=Carbon dioxide increases with face masks but remains below short-term NIOSH limits | date=2021 | last1=Rhee | first1=Michelle S. M. | last2=Lindquist | first2=Carin D. | last3=Silvestrini | first3=Matthew T. | last4=Chan | first4=Amanda C. | last5=Ong | first5=Jonathan J. Y. | last6=Sharma | first6=Vijay K. | journal=BMC Infectious Diseases | volume=21 | issue=1 | page=354 | pmid=33858372 | pmc=8049746 }}</ref> In various surveys among healthcare workers, [[headache]]s,<ref>{{cite journal |url=https://doi.org/10.1007/s11916-021-00968-x | doi=10.1007/s11916-021-00968-x | title=Headache Related to PPE Use during the COVID-19 Pandemic | date=2021 | last1=Ong | first1=Jonathan J. Y. | last2=Chan | first2=Amanda C. Y. | last3=Bharatendu | first3=Chandra | last4=Teoh | first4=Hock Luen | last5=Chan | first5=Yee Cheun | last6=Sharma | first6=Vijay K. | journal=Current Pain and Headache Reports | volume=25 | issue=8 | page=53 | pmid=34129112 | pmc=8203491 }}</ref> [[dermatitis]] and [[acne]] have been reported.<ref name="Goh-2006">{{cite journal |author1=Chris C.I. Foo|author2=Anthony T.J. Goon|author3=Yung-Hian Leow|author4=Chee-Leok Goh |title=Adverse skin reactions to personal protective equipment against severe acute respiratory syndrome – a descriptive study in Singapore |journal=Contact Dermatitis |date=2006 |volume=55 |issue=5 |pages=291–294 |doi=10.1111/j.1600-0536.2006.00953.x |publisher=John Wiley & Sons |pmid=17026695 |pmc=7162267 |language=en |issn=0105-1873|doi-access=free }}</ref>

Complaints have been leveled at early [[Los Alamos National Laboratory|LANL]] NIOSH fit test panels (which included primarily military personnel) as being unrepresentative of the broader American populace.<ref>{{cite web|url=https://www.cdc.gov/niosh/docket/archive/pdfs/NIOSH-137/0137-081809-DraftNIOSHReport.pdf|title=Determination of Sample Size and Passing Criteria for Fit Test Panels|access-date=3 June 2024|archive-date=8 August 2023|archive-url=https://web.archive.org/web/20230808002256/https://www.cdc.gov/niosh/docket/archive/pdfs/NIOSH-137/0137-081809-DraftNIOSHReport.pdf|url-status=live}}</ref> However, later fit test panels, based on a NIOSH facial survey conducted in 2003, were able to reach 95% representation of working US population surveyed.<ref>{{cite journal |url=http://dx.doi.org/10.1080/15459620701497538 | doi=10.1080/15459620701497538 | title=New Respirator Fit Test Panels Representing the Current U.S. Civilian Work Force | date=2007 | last1=Zhuang | first1=Ziqing | last2=Bradtmiller | first2=Bruce | last3=Shaffer | first3=Ronald E. | journal=Journal of Occupational and Environmental Hygiene | volume=4 | issue=9 | pages=647–659 | pmid=17613722 | url-access=subscription }}</ref> Despite these developments, 42 CFR 84, the US regulation NIOSH follows for respirator approval, allows for respirators that don't follow the NIOSH fit test panel provided that: more than one facepiece size is provided, and no chemical cartridges are made available.<ref>§135, §198, and §205. {{cite web|url=https://www.ecfr.gov/current/title-42/chapter-I/subchapter-G/part-84|title=PART 84—APPROVAL OF RESPIRATORY PROTECTIVE DEVICES|access-date=3 June 2024|archive-date=15 March 2024|archive-url=https://web.archive.org/web/20240315131316/https://www.ecfr.gov/current/title-42/chapter-I/subchapter-G/part-84|url-status=live}}</ref>

=== Issues with lack of regulation ===
Respirators designed to non-US standards may not be subject to as much or any scrutiny:
* In China, under GB2626-2019, which includes standards like KN95, there is no procedure for [[Respirator fit test|fit testing]].<ref>{{cite web |url=https://openstd.samr.gov.cn/bzgk/gb/newGbInfo?hcno=16D8935B45AD7AE40228801B7FADFC6C |title=国家标准&#124;Gb 2626-2019 |access-date=3 June 2024 |archive-date=3 June 2024 |archive-url=https://web.archive.org/web/20240603192044/https://openstd.samr.gov.cn/bzgk/gb/newGbInfo?hcno=16D8935B45AD7AE40228801B7FADFC6C |url-status=live }}</ref>
Some jurisdictions allow for respirator filtration ratings lower than 95%, respirators which are ''not'' rated to prevent respiratory infection, asbestos, or other dangerous occupational hazards. These respirators are sometimes known as [[dust mask]]s for their almost exclusive approval only against dust nuisances:
* In Europe, regulation allows for [[dust mask]]s under [[FFP standards|FFP1]], where 20% inward leakage is allowed, with a minimum filtration efficiency of 80%.<ref>{{cite web|url=https://www.moldex-europe.com/en/moldex-good-to-know/protection-levels-ffp1-masks-ffp2-masks-ffp3-masks/|title=Protection levels: FFP1 masks, FFP2 masks, FFP3 masks|publisher=Moldex Europe|access-date=3 June 2024|archive-date=2 June 2024|archive-url=https://web.archive.org/web/20240602194300/https://www.moldex-europe.com/en/moldex-good-to-know/protection-levels-ffp1-masks-ffp2-masks-ffp3-masks/|url-status=live}}</ref>
* South Korea allows 20% filter leakage under [[Mechanical filter (respirator)#Other standards (KN95 and others)|KF80]].
In the US, NIOSH noted that under standards predating the [[N95 respirator#History|N95]], 'Dust/Mist' rated respirators could not prevent the spread of [[tuberculosis|TB]].<ref>{{cite web|url=https://archives.federalregister.gov/issue_slice/1994/10/28/54237-54364.pdf|title=DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention Guidelines for Preventing the Transmission of Mycobacterium Tuberculosis in Health-Care Facilities, 1994|publisher=US Federal Register|access-date=2024-05-08|archive-date=8 June 2024|archive-url=https://web.archive.org/web/20240608020741/https://archives.federalregister.gov/issue_slice/1994/10/28/54237-54364.pdf|url-status=live}}</ref>