N95 respirator - Knowledge

891: 1095:(CDC) has recommended strategies for optimizing their use in healthcare settings. N95 respirators can be used beyond their manufacturer-designated shelf life, although components such as the straps and nose bridge material may degrade, making it particularly important that the wearer perform the expected seal check. N95 respirators can be reused a limited number of times after being removed, as long as they have not been used during aerosol-generating procedures and are not contaminated with patients' bodily fluids, because this increases the risk of surface contamination with pathogens. The respirator manufacturer may recommend a maximum number of donnings or uses; if no manufacturer guidance is available, preliminary data suggests limiting to five uses per device. Respirators approved under standards used in other countries and are similar to NIOSH-approved N95 respirators—including 1225: 173: 875: 883: 1016: 1677: 299: 1496: 781: 349: 669: 147: 1344: 730: 5493: 1867: 1322:, like hospitals, where many patients infected with TB were also infected with HIV. The proposed rule would require signage that includes a STOP sign, with red background, white symbols, and a set of words warning people to wear "N95 or more protective" respirators (under 42 CFR 84) near isolation rooms where TB infection is likely. Additional notices could be added at the discretion of an employer, so long as it did not contradict the required wording. 1555:, and to keep them within the U.S. instead. However, 3M refused, saying: "Ceasing all export of respirators produced in the United States would likely cause other countries to retaliate and do the same, as some have already done. If that were to occur, the net number of respirators being made available to the United States would actually decrease. That is the opposite of what we and the administration, on behalf of the American people, both seek." 246:. An authentic N95 respirator is marked with the text "NIOSH" or the NIOSH logo, the filter class ("N95"), and, for most filtering facepiece respirators (respirators with non-replaceable filters), a "TC" approval number of the form 84A-####, the approval number. All N95 respirators, regardless of type, must be listed on the NIOSH Certified Equipment List (CEL) or the NIOSH Trusted-Source page, and it must have headbands instead of ear loops. 125: 5517: 1790: 1284: 5505: 677: 1751: 3675: 3639: 3308: 3185: 2620: 1712: 1699: 725: 1311:, which would require more rigorous standards to mitigate, especially since they felt that the 1990 CDC guidelines for TB were not being properly followed. The CDC eventually revised and released new TB guidelines in 1994, and in 1995 and 1996, meetings started to be held between OSHA and various stakeholders for a new TB standard, borrowing heavily from the CDC's work. 1837: 1738: 1725: 1817: 1915: 697: 363: 1764: 1126:; physical barriers such as clear windows; allowing only those involved in direct care to enter a room with a COVID-19 patient; using only the PPE necessary for the specific task; continuing use of the same respirator without removing it while caring for multiple patients with the same diagnosis; monitoring and coordinating the PPE 2810: 735: 1803: 1367:

confusion over respirator procedures, and the insinuation by various infection control practitioners that N95 respirators were not necessary. However, the report concludes, from laws preceding SARS, healthcare workers were obligated to wear N95 respirators throughout the outbreak, despite suggestions to the contrary.

321:, these standards were merely advisory, as the USBM had no enforcement power at the time. After the disaster, an explicit approval program was established in 1934, along with the introduction of combination Type A/B/C respirator ratings, corresponding to Dusts/Fumes/Mists respectively, with Type D blocking all three. 1777: 1850: 1147:

filters may also be used to increase ventilation in isolation rooms when surgical masks are being used in place of respirators. If neither respirators nor surgical masks are available, as a last resort, it may be necessary for healthcare workers to use masks that have never been evaluated or approved

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is not available, as a respirator will still provide better protection than a surgical mask or no mask. In this case, best practices for getting a good face seal include trying different models or sizes, using a mirror or asking a colleague to check that the respirator is touching the face, and doing

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In industrial settings where infectious disease exposure is not a concern, users can wear and reuse a filtering facepiece respirator until it is damaged, soiled, or causing noticeably increased breathing resistance, unless there is a manufacturer-specified duration of use. However, in laboratories at

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was in full force at the time) was noted to be one of the strongest factors for TB activation, since most TB outbreaks and mortalities reported at the time involved healthcare workers and patients infected with HIV. Respiratory protection and the performance of respirators were emphasized in the 1994

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Lyngse FP, Mortensen LH, Denwood MJ, Christiansen LE, Møller CH, Skov RL, Spiess K, Fomsgaard A, Lassaunière R, Rasmussen M, Stegger M, Nielsen C, Sieber RN, Cohen AS, Møller FT, Overvad M, Mølbak K, Krause TG, Kirkeby CT (September 2022). "Household transmission of the SARS-CoV-2 Omicron variant in

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The CDC recommends farm workers wear PPE, including N95 or better respirators, when working with farm animals potentially infected with H5N1. However, outbreaks of H5N1 have continued among dairy workers, likely due to workers' fear of retaliation by their employers, and reluctance by employers and

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interim guide for H1N1 recommended N95 respirators for the prevention of H1N1, but stopped short of recommending respirators for groups not deemed "at increased risk of severe illness from influenza", except for occupational use in healthcare. NIOSH also emphasized the differences in fit between an

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and maintaining distance from the patient are particularly important to reduce the risk of transmission. When no respirators are left, workers who are at higher risk for severe illness may be excluded from caring for patients, and workers who have clinically recovered from COVID-19 may be preferred

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When it is no longer possible for all healthcare workers to wear N95 respirators when caring for a COVID-19 patient, the CDC recommends that respirators be prioritized for workers performing aerosol-generating procedures on symptomatic persons, and those within three feet of an unmasked symptomatic

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Before use of a respirator can be mandated by an employer, OSHA regulations require a medical evaluation. In the United States medical evaluation is required once, prior to initial fit testing and use, although it may need to be repeated if any adverse signs or symptoms are observed. Correct use of

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To quickly address the HEPA-only respirator requirement for TB controls, stemming from the lack of biological protection in the existing 30 CFR 11 standards (which were mainly designed for miners), NIOSH aimed to have the proposed 42 CFR rule changes finished by the end of 1994. The proposal at the

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may have been due to relaxing of policies preventing COVID-19 transmission (like source control policies). The 2023 paper also cites a research letter published in 2022, that suggests that the surge of COVID-19 cases in hospitals may have been due to the high contagiousness of Omicron, an article

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After the 2009 H1N1 flu season, the CDC issued guidelines recommending surgical masks instead, after complaints were leveled by various groups on the effectiveness of surgical masks compared to N95 respirators, along with complaints about comfort. The new recommendations were met with approval by

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Meanwhile, in Canada, discussions with Ontario EMS and New York Department of Health in 2004 noted that infected emergency medical personnel failed to properly use N95 respirators. According to Ontario SARS commission final report, this was likely due to confusion over infectious disease control,

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In 2003, in response to the SARS outbreak, the United States CDC advised healthcare workers to wear N95 respirators. Despite this advice, a patient who had traveled from Ontario exposed six healthcare workers in Pennsylvania following contact tracing by the CDC, though fitted N95 respirators were

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A surgical mask may not block all particles, due to the lack of fit between the surface of the face mask and the face. The filtration efficiency of a surgical mask ranges between 10% to 90% for any given manufacturer, when measured using tests required for NIOSH certification. A study found that

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30 CFR 11. On July 10, 1995, in response to respirators exhibiting "low initial efficiency levels", new 42 CFR 84 standards, including the N95 standard, were enforced under a three-year transition period, ending on July 1, 1998. The standard for N95 respirators includes, but is not limited to, a

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A later preprint study by the same lead author (Loeb) claiming the same thing was found to be fraudulent in multiple ways, including use of unregistered study sites, repeated alteration of mathematical analysis methods to obscure the evidence in the data, as well as concealment of conflicts of

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studies of masks started being done, comparing surgical masks and N95 respirators with the tendency for medical staff to be infected by the flu. One paper concluded that N95s were better than surgical masks, but its results were later called into question. Another paper claimed that protection

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to prevent the spread of diseases like COVID-19 when worn by asymptomatic infected users, at a level similar to that of a surgical or cloth facemask, although it is not equivalent to the performance of unvalved respirators. The same study found that "odifications can further reduce particle

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noted that the CDC had dropped mandates for masks in hospitals during COVID, limiting the COVID policies to an advisory role. Use of masks for source control is still recommended in times of high viral activity, but the CDC did not provide numbers for benchmarks. The new policies are thought,

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was tasked with reducing the incidences of hospital acquired TB infections. TB infections had traditionally occurred mainly in underserved groups and areas, as well as the very young and elderly, but regardless, usually had around a 10% chance of turning into an active TB infection in a given

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time would drop the HEPA classification for non-powered respirators, and add three respirator types, at the time called Type A, B and C, with filtration efficiencies of greater than or equal to 99.97%, 99%, and 95% respectively, with Type C corresponding to the current N95 standard.

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According to NIOSH, all the new respirator types proposed in 42 CFR 84, including Type C (later N95), would meet the CDC's requirement for protection against TB, and would provide avenues for cheaper NIOSH-approved respirators without the need for HEPA or NIOSH class-100 filters.

1031:. These may also be labeled "Surgical N95", "medical respirators", or "healthcare respirators". The difference lies in the extra fluid-resistant layer outside, typically colored blue. In addition to 42 CFR 84, surgical N95s are regulated under FDA regulation 21 CFR 878.4040. 317:(USBM). An example of an early respirator standard, Type A, established in 1926, was intended to protect against mechanically generated dusts produced in mines. These standards were intended to obviate miner deaths, noted to have reached 3,243 by 1907. However, prior to the 1160:

Disposable filtering facepiece respirators such as N95 respirators are not approved for routine decontamination and reuse as standard of care. However, their decontamination and reuse may need to be considered as a crisis capacity strategy to ensure continued availability.

1906: 717: 1888: 707: 905:(US) requires an initial respirator fit test to identify the right model, style, and size respirator for each worker; as well, as annual fit tests. Additionally, tight-fitting respirators, including the N95, require a user seal check each time one is put on. 4124: 1459:

For those in the general public wishing to wear N95 respirators, properly wearing a N95 was noted to be difficult, but the tendency for people to distance themselves from those wearing masks complimented the six-foot social distancing rules at the time.

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Some industrial N95 series respirators have an exhaust valve to improve comfort, making exhalation easier, reducing leakage on exhalation and steaming-up of glasses. Research has indicated that wearing a valved N95 respirator does provide some

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N95 respirators are considered similar to other respirators regulated under non-U.S. jurisdictions, but slightly different criteria are used to certify their performance, such as the filter efficiency, test agent and flow rate, and permissible

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stated there were harms in continued undue weight being placed on RCTs and flawed mask studies in a social and political context, as retracted papers continue to be circulated to justify certain masking behaviors and beliefs. One retracted

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Greenhalgh, Trisha; MacIntyre, C. Raina; Baker, Michael G.; Bhattacharjee, Shovon; Chughtai, Abrar A.; Fisman, David; Kunasekaran, Mohana; Kvalsvig, Amanda; Lupton, Deborah; Oliver, Matt; Tawfiq, Essa; Ungrin, Mark; Vipond, Joe (2024).

1510:, filed a trademark application on June 17, 2020 for various 42 CFR 84 trademarks, including the N95, allowing NIOSH to enforce rules on counterfeit masks outside of rules defined in 42 CFR 84. The trademarks were registered in 2022. 1259:

A CDC study found that in public indoor settings, consistently wearing a respirator was linked to a 83% lower risk of testing positive for COVID-19, as compared to a 66% reduction when using surgical masks, and 56% for cloth.

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and forms the inner filtration layer that filters out hazardous particles. However, the N95 standard does not preclude alternative means of filtration, so long as the respirator meets N95 standards and is approved by NIOSH.

4095:""Medical masks versus N95 respirators for preventing COVID-19 among health care workers: A secondary analysis of findings inconsistent with prior understanding reflects the expected inferiority of medical masks"" 1621:

Following previous H1N1 randomized control trials comparing N95s and surgical masks, new RCTs were published. Major flaws were noted, including contraction of virus outside hospital, the lack of controls over

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to wear respiratory protection, such as an N95 respirator. The CDC recommends the use of respirators with at least N95 certification to protect the wearer from inhalation of infectious particles including

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Svoboda, Tomislav; Henry, Bonnie; Shulman, Leslie; Kennedy, Erin; Rea, Elizabeth; Ng, Wil; Wallington, Tamara; Yaffe, Barbara; Gournis, Effie; Vicencio, Elisa; Basrur, Sheela; Glazier, Richard H. (2004).

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Potter AL, Vaddaraju V, Venkateswaran S, Mansur A, Bajaj SS, Kiang MV, Jena AB, Yang CJ (October 2023). "Deaths Due to COVID-19 in Patients With Cancer During Different Waves of the Pandemic in the US".

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start stocking PPE and N95 respirators in the event of another SARS outbreak. It was noted at the time that there were few N95 respirator manufacturers, potentially exacerbating a shortage in a crisis.

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There have been efforts to evaluate cleaning methods for respirators in emergency shortages, although there is concern that this may reduce filter performance, or affect mask fit by deforming the mask.

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is designed to provide barrier protection against droplets and does not have an air-tight seal and thus does not protect its wearer against airborne particles such as virus material to the same extent.

2290: 1801:, Elvin L. Boyce & William Keith Robinson, "Filter mask", published 1976-10-12, issued 1976-10-12, assigned to Kimberly-Clark Worldwide Inc. and Alpha Pro Tech Inc. 1788:, Joseph P. Kronzer, Roger J. Stumo, James F. Dyrud, Harvey J. Berg, "Methods of forming fibrous filtration face masks", published 1994-05-03, issued 1994-05-03, assigned to 3M Co 2637: 943:

According to the NIOSH Respirator Selection Logic, respirators with filters in the N, R, and P series are recommended for concentrations of hazardous particulates that are greater than the relevant

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provided by an N95 respirator compared similarly to a surgical mask, but the study did not control health care personnel potentially being exposed outside, without respirators, via the community.

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OSHA does not currently have any standards for disinfecting N95 respirators. NIOSH recommends that during shortages N95 respirators may be used up to five times without cleaning them, as long as

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Once 42 CFR 84 was in effect, MSHA, under a proposed rule change to 30 CFR 11, 70, and 71, would withdraw from the approval process of rated respirators (outside of respirators used for mining).

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are expected to meet at least 95% filtration. However, NIOSH found that some products labeled "KN95" failed to meet these standards, some of them filtering out as little as one percent. Both the

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Loeb, Mark; Dafoe, Nancy; Mahony, James; John, Michael; Sarabia, Alicia; Glavin, Verne; Webby, Richard; Smieja, Marek; Earn, David J. D.; Chong, Sylvia; Webb, Ashley; Walter, Stephen D. (2009).

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OSHA withdrew the proposal in 2003, owing to commenters and reviewers pointing to a likely overstating of risk, declining rates of TB in the years following the proposal, as well as compliance

4745: 1451:, and the waiving of certain quality controls on certain models of newly manufactured N95 respirators, provided they were documented "for use during the swine flu emergency". Initially, the 2469:"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" 1749:, James F. Dyrud, Harvey J. Berg, Alice C. Murray, "Resilient shape-retaining fibrous filtration face mask", published 1989-02-28, issued 1989-02-28, assigned to 3M Co 340:, establishing NIOSH, as well as other regulations established around the time, reshuffled regulatory authority for respirators, but nonetheless continued the use of USBM-era regulations. 2499:. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health. September 1999. 1303:

While NIOSH was busy finishing 42 CFR 84 respirator regulations (including the N95), other agencies and groups were advocating for new standards for the prevention of TB. In 1992, the

4609:"Notice of Retraction. Walach H, et al. Experimental Assessment of Carbon Dioxide Content in Inhaled Air with or Without Face Masks in Healthy Children: A Randomized Clinical Trial. 4185: 1399:

be required, so long as it was limited to "routine entry", patients were not confirmed to be infected, and no aerosol-generating procedures were being done. "Standard precautions"

3504:"Decontamination and Reuse of N95 Respirators with Hydrogen Peroxide Vapor to Address Worldwide Personal Protective Equipment Shortages During the SARS-CoV-2 (COVID-19) Pandemic" 2089: 829:

After the passage of 42 CFR 84, a 1999 NIOSH guide for health care administrators noted that respirators selected for TB prevention under 42 CFR would likely be N95 respirators.

7290: 396: 4570:"Proposed Update to Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings (2007), 'Protective Environment' Recommendation" 3032:(Publication No. 2021-107). U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health. 3786:"Part III DEPARTMENT OF LABOR Occupational Safety and Health Administration 29 CFR Part 1910 [Docket No. H-371] RIN 1218-AB46 Occupational Exposure to Tuberculosis" 1710:, David L. Braun, "Particle-loaded microfiber sheet product and respirators made therefrom", published 1976-07-27, issued 1976-07-27, assigned to 3M Co 1951: 1897: 712: 188:

Thoroughly check the NIOSH Certified Equipment List, and compare the look and feel to known good respirators to verify that a suspect respirator is a NIOSH-approved N95.

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require such KN95 products failing to meet the filtration standards to be re-labeled as "face masks" instead of "respirators", when being sold in the U.S. and Canada.

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union, as they felt the changes did not go far enough. Changes included clarifying by adding "source control" as a qualification for the use of "barrier precautions".

3592: 1697:, Robert J Barghini, Walter M Westberg, Patrick H Carey Jr, "Cold weather face mask", published 1967-08-01, issued 1967-08-01, assigned to 3M Co 1023:

Respirators used in healthcare are traditionally a specific variant called a surgical respirator, which is both approved by NIOSH as a respirator and cleared by the

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officials reported that the supply of respirators and other PPE in the stockpile was nearly gone. Respirators came to be in short supply and high demand during the

5555: 3754:"DEPARTMENT OF LABOR Occupational Safety and Health Administration 29 CFR Part 1910 [Docket No. H-371] RIN 1218-AB46 Occupational Exposure to Tuberculosis" 3620: 75:

under 21 CFR 878.4040, in addition to NIOSH 42 CFR 84. 42 CFR 84, the federal standard which the N95 is part of, was created to address shortcomings in the prior

4141: 1866: 1723:, Donald A. Kubik & Charles I. Davis, "Melt-blown fibrous electrets", published 1980-08-05, issued 1980-08-05, assigned to 3M Co 4819: 230:; two other standards, R95 and P95, add that requirement. The N95 type is the most common filtering facepiece respirator. Current filters are an example of a 6439: 4125:"From Scarcity to Abundance: Complementary Government and Private Initiatives to Manage the Allocation of N95 Masks in the U.S. During the COVID-19 Pandemic" 449: 215: 56: 1579:

according to the New York Times, based on various citations to medical literature, to increase mortality among vulnerable patients, especially those with

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in Toronto, that "N95 or higher respirators may offer additional protection to those exposed to aerosol-generating procedures and high risk activities".

505: 3503: 510: 337: 4256: 4204: 2239: 1835:, Kevin K. Brunson, "Disposable Aerosol Mask", published 1994-06-21, issued 1998-06-02, assigned to Kimberly-Clark Worldwide Inc. 1432:

for new facilities, and use of fitted N95 respirators. These measures should be used whenever someone is suspected of harboring an "infectious agent".

2268: 3694:"Effectiveness of Face Mask or Respirator Use in Indoor Public Settings for Prevention of SARS-CoV-2 Infection — California, February–December 2021" 3561: 916:

For persons who are medically disqualified from negative-pressure respirators, or who cannot pass a fit test due to facial hair or other reasons, a

4155: 3203:"Release of Stockpiled N95 Filtering Facepiece Respirators Beyond the Manufacturer-Designated Shelf Life: Considerations for the COVID-19 Response" 2782: 1519: 970:. For substances hazardous to the eyes, a respirator equipped with a full facepiece, helmet, or hood is recommended. They are not effective during 4793: 5044: 3488: 2068: 418: 325: 4652:"Retraction: Physio-metabolic and clinical consequences of wearing face masks—Systematic review with meta-analysis and comprehensive evaluation" 3026:"Filtering Facepiece Respirators with an Exhalation Valve: Measurements of Filtration Efficiency to Evaluate Their Potential for Source Control" 1848:, "Face mask with enhanced seal and method", published 1997-12-09, issued 1997-12-09, assigned to Kimberly-Clark Worldwide Inc. 1278: 6877: 767: 4852: 2912: 1403:

the use of masks, face shields, and/or eye protection, would be needed if there was potential for the spraying of bodily fluids, like during

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started lobbying OSHA to create advisories and formal rules to protect workers from TB. The group was especially concerned about the rise of

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Gong IY, Vijenthira A, Powis M, Calzavara A, Patrikar A, Sutradhar R, Hicks LK, Wilton D, Singh S, Krzyzanowska MK, Cheung MC (March 2023).

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NIOSH Recommended Guidelines for Personal Respiratory Protection of Workers in Health-Care Facilities Potentially Exposed to Tuberculosis

1038:(OSHA) requires healthcare workers who are expected to perform patient activities with those suspected or confirmed to be infected with 2916: 1736:, Harvey J. Berg, "Molded fibrous filtration products", published 1985-08-20, issued 1985-08-20, assigned to 3M Co 1506:

During the COVID-19 pandemic, the mask and respirator market rapidly grew, along with counterfeit respirators. NIOSH, on behalf of the

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concluded that universal use of N95 respirators, as well as additional infection control measures, ended the SARS outbreak in Ontario.

1092: 937: 805: 428: 3166: 2291:"Certain Filtering Facepiece Respirators from China May Not Provide Adequate Respiratory Protection - Letter to Health Care Providers" 4109: 2027: 1785: 1759: 1733: 1720: 1707: 1565: 1384: 4393:"Association of Omicron vs Wild-type SARS-CoV-2 Variants With Hospital-Onset SARS-CoV-2 Infections in a US Regional Hospital System" 3289: 1772: 1746: 1694: 1536:

and hoarding, often leading to confiscation of masks. Production of N95 respirators was limited due to constraints on the supply of

890: 4593: 4283: 3257: 3105: 7285: 5541: 4569: 1946: 1507: 948: 472: 7212: 7199: 5813: 5569: 3540: 1963: 952: 1815:, Elvin L. Boyce, "Filter mask", published 1987-04-25, issued 1987-04-25, assigned to Alpha Pro Tech Inc. 1410:

The guidelines are the same regardless of the type of pathogen, but the guidelines also note that, based on the experience of

6484: 2335: 1988: 842: 467: 434: 333: 5826: 4171:"Depleted National Stockpile Contributed to COVID PPE Shortage: 'You Can't Be Prepared If You're Not Funded to Be Prepared'" 3942: 7001: 6459: 5509: 2519:"DEPARTMENT OF HEALTH AND HUMAN SERVICES Public Health Service 42 CFR Part 84 RIN 0905–AB58 Respiratory Protective Devices" 1941: 1003: 628: 477: 172: 88: 3079: 2662: 1762:, Martin R. Skov, "Face mask", published 1989-07-25, issued 1989-07-25, assigned to Moldex Metric Inc 1256:

80–100% of subjects failed an OSHA-accepted qualitative fit test, and a quantitative test showed between 12–25% leakage.

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Hui, David S.; Chow, Benny K.; Chu, Leo; Ng, Susanna S.; Lee, Nelson; Gin, Tony; Chan, Matthew T. V. (December 5, 2012).

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showed the most promise as potential methods to decontaminate N95 respirators and other filtering facepiece respirators.

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While discussions for overhauling existing respirator regulations had been discussed since the late 1980s, in 1992, the

7204: 4962: 4897: 3232:"Recommended Guidance for Extended Use and Limited Reuse of N95 Filtering Facepiece Respirators in Healthcare Settings" 1657: 1447:

In May of 2009, in response to the H1N1 swine flu outbreak, the CDC authorized the release of N95 respirators from the

1205: 979: 760: 633: 6208: 3880:"Public Health Measures to Control the Spread of the Severe Acute Respiratory Syndrome during the Outbreak in Toronto" 2938: 6634: 6629: 5255: 4967: 4874: 4845: 1630: 1054: 271: 6239: 2543: 2312: 1204:

when donning and seal-checking a used N95 respirator and discarding the gloves immediately after. According to CDC,

7173: 6713: 6120: 5736: 5415: 5400: 4989: 1544: 1308: 917: 801: 3991: 3463: 2834:"Building a Safety Program to Protect the Nanotechnology Workforce: A Guide for Small to Medium-Sized Enterprises" 2576: 2493: 2411: 6307: 3130: 1992: 1525: 1371: 689: 684: 4257:"3 million masks ordered by Massachusetts were confiscated in Port of New York, leading to creative alternative" 4223: 958:

N series respirators, including the N95 respirator, are only effective in the absence of oil particles, such as

7048: 6646: 6365: 6343: 5774: 5224: 5151: 4974: 3992:"Interim Recommendations for Facemask and Respirator Use to Reduce Novel Influenza A (H1N1) Virus Transmission" 3923:"2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings" 3829: 3800: 2196: 2130: 1926: 231: 135: 3860: 3231: 2468: 874: 318: 7016: 5714: 5039: 3132:

2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings

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2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings

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2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings

1274: 1115: 814: 753: 414: 357: 314: 84: 76: 4486:"Association of COVID-19 Vaccination With Breakthrough Infections and Complications in Patients With Cancer" 4330: 3514: 901:

is a critical component to a respiratory protection program whenever workers use tight-fitting respirators.

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article cites a paper published in 2023, that suggests the high mortality of cancer patients following the

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with N95 filters installed. Note the lack of a TC number; TC numbers are absent on elastomeric respirators.

72: 5868: 4205:"Feds have 1.5 million expired N95 masks in storage despite CDC clearing them for use on COVID-19: report" 4025: 2443: 1524:

The Strategic National Stockpile had not been refilled following the H1N1 pandemic, and by April of 2020,

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guidelines to controlling TB, which, at the time, were limited to respirators equipped with HEPA filters.

7260: 7085: 6956: 6892: 6860: 6808: 6105: 6087: 5410: 5395: 5067: 5027: 3569: 3562:"Duke Researchers Find Way to Decontaminate and Reuse N95 Masks, Possibly Alleviating Critical Shortfall" 3327:"N95 Filtering Facepiece Respirators during the COVID-19 Pandemic: Basics, Types, and Shortage Solutions" 1996: 1936: 1338: 1233: 1209: 1178: 1174: 975: 944: 850: 789: 560: 543: 500: 38: 3593:"FDA lifts restrictions on Ohio-based Battelle's mask-sterilizing technology amid coronavirus shortages" 3541:"Duke researchers are decontaminating N95 masks so doctors can reuse them to treat coronavirus patients" 3202: 3053: 2602: 2577:"CHANGES IN OCCUPATIONAL SAFETY REGS WILL PERMIT BETTER RESPIRATORS TO PROTECT AGAINST DUST AND DISEASE" 882: 6641: 6054: 5794: 5380: 5306: 4814: 1907:

Differences and Limitations Between Part 11 Particulate Respirators and Part 84 Particulate Respirators

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researchers have published a method for cleaning N95 respirators without damaging them using vaporized

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Changes in Occupational Safety Regs Will Permit Better Respirators to Protect Against Dust and Disease

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level and the manufacturer's maximum use concentration, subject to the respirator having a sufficient

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Changes in Occupational Safety Regs Will Permit Better Respirators to Protect Against Dust and Disease

7145: 7135: 6830: 6766: 6489: 6454: 6257: 6234: 6020: 5833: 5442: 5137: 2518: 1775:, Jerome H. Lemelson, "Face mask and method", published 1989-08-15, issued 1989-08-15 1119: 590: 17: 2756: 7280: 7275: 6963: 6825: 6700: 6554: 5669: 5659: 5146: 5120: 3966: 2217: 2050: 1595: 1469: 1213: 2904: 7150: 7068: 6934: 6464: 6262: 5969: 5907: 5741: 5709: 5457: 5425: 5370: 5277: 5193: 4957: 4890: 4767: 4288: 3376:

Viscusi, Dennis J.; Bergman, Michael S.; Eimer, Benjamin C.; Shaffer, Ronald E. (November 2009).

2878: 1442: 1348: 1015: 595: 104: 5821: 7265: 6737: 6522: 6272: 6145: 5751: 5608: 5598: 5009: 4704:"Masks and respirators for prevention of respiratory infections: A state of the science review" 1957:

Impact of the COVID-19 pandemic on neurological, psychological and other mental health outcomes

1676: 1609: 1599: 1537: 983: 643: 199: 179: 52: 3785: 2561:

Herring Jr., Ronald N. (1997). "42 CFR Part 84: It's time to change respirators... but how?".

1192:-generating procedures are not performed, and respirators are not contaminated with patients' 982:

is recommended instead. They are not effective against hazardous gases or vapors, for which a

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Guidance for performing a user seal check, which is required every time a respirator is put on

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Also in 2023, new draft guidelines were proposed by the CDC HICPAC, to update the pre-COVID

1420:", a specific protocol for "infectious agents transmitted by the airborne route", like with 7270: 7140: 7033: 6979: 6907: 6897: 6589: 6444: 6317: 5924: 5533: 5375: 5270: 4450: 4010: 3657: 3024:

Portnoff, L; Schall, J; Brannen, J; Suhon, N; Strickland, K; Meyers, J (December 1, 2020).

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Following the SARS outbreak in the US, US Senate hearings started to be held proposing the

1245: 648: 48: 31: 4304: 3054:"A Comparison of Surgical Masks, Surgical N95 Respirators, and Industrial N95 Respirators" 1395:, suggesting that use of "barrier precautions", defined as "masks, gowns, gloves", would 218:. It is illegal in the United States to use the term "N95" without the approval of NIOSH. 8: 7227: 7217: 7183: 6788: 6226: 6062: 5873: 5462: 5405: 5173: 5156: 5132: 5078: 4861: 3814: 3436: 2116:

NIOSH Guide to the Selection and Use of Particulate Respirators Certified Under 42 CFR 84

1880:

NIOSH Guide to the Selection and Use of Particulate Respirators Certified Under 42 CFR 84

1107: 1062: 898: 4678: 4651: 4510: 4485: 4454: 3922: 2757:"Understanding respiratory protection options in healthcare: the overlooked elastomeric" 2705: 2690:"Exhaled Air Dispersion during Coughing with and without Wearing a Surgical or N95 Mask" 1626:

in hospital, and assumptions made about transmission via droplets instead of aerosols.

6951: 6946: 6855: 6835: 6469: 6312: 6277: 6131: 6097: 5647: 5420: 5260: 5235: 4996: 4417: 4392: 3718: 3410: 3377: 3353: 3326: 3258:"Rational use of personal protective equipment for coronavirus disease 2019 (COVID-19)" 2967: 2732: 2689: 2373: 2356: 1574: 1058: 741: 638: 298: 60: 5883: 4576: 3917: 3915: 3913: 3693: 3167:"Strategies for Optimizing the Supply of N95 Respirators: Crisis/Alternate Strategies" 7237: 7178: 7038: 6991: 6793: 6295: 5964: 5954: 5944: 5929: 5746: 5729: 5593: 5474: 5469: 5452: 5245: 5166: 4950: 4727: 4683: 4632: 4628: 4551: 4515: 4466: 4422: 4373: 4231: 4075: 3899: 3723: 3482: 3415: 3397: 3358: 2737: 2719: 2378: 2090:"COVID-19 Has Caused A Shortage Of Face Masks. But They're Surprisingly Hard To Make" 1529: 1500: 1490: 1170: 1088: 668: 303: 195: 131: 108: 4056:"Surgical Mask vs N95 Respirator for Preventing Influenza Among Health Care Workers" 3937: 3935: 2240:"Comparison of FFP2, KN95, and N95 and Other Filtering Facepiece Respirator Classes" 1495: 7232: 7168: 7155: 6984: 6973: 6865: 6845: 6680: 6594: 6569: 6300: 6247: 6186: 6077: 5724: 5652: 5198: 4810: 4723: 4715: 4673: 4663: 4624: 4608: 4543: 4505: 4497: 4458: 4412: 4404: 4365: 4067: 3910: 3891: 3713: 3705: 3405: 3389: 3348: 3338: 3033: 2975: 2851: 2841: 2727: 2709: 2500: 2494:"TB Respiratory Protection Program In Health Care Facilities Administrator's Guide" 2368: 2131:"NIOSH-Approved N95 Particulate Filtering Facepiece Respirators - A Suppliers List" 2073: 1598:, and papers finding increased mortality of cancer patients due to higher rates of 1106:

According to NIOSH, respirators may still be used in crisis situations if standard

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During crisis situations where there is a shortage of N95 respirators, such as the

785: 7100: 7095: 6939: 6887: 6695: 6672: 6517: 6494: 5878: 5843: 5719: 5664: 4156:"NIOSH Registers Respirator Certification Marks with Patent and Trademark Office" 3949: 3932: 2714: 2114: 1643: 1547:, invoking the DPA, ordered 3M to stop exporting N95 respirators to customers in 1166: 1149: 1050: 995: 991: 855: 5848: 4547: 4501: 4369: 3767: 3378:"Evaluation of Five Decontamination Methods for Filtering Facepiece Respirators" 1138:

person. Under these conditions, masking of symptomatic patients with at least a

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Terrorism and CBRN defense (with SCBAs) meeting by NIOSH, circa March-April 2001

7130: 7063: 6778: 6667: 6659: 6584: 6537: 6532: 6479: 6203: 5984: 5979: 5939: 5888: 5853: 5691: 5627: 5320: 5127: 5098: 4668: 4462: 1685: 1100: 287: 259: 3464:"Doctors scramble for best practices on reusing medical masks during shortage" 2885:. U.S. National Institute for Occupational Safety and Health. December 7, 2011 2444:"DEPARTMENT OF HEALTH AND HUMAN SERVICES Public Health Service 42 CFR Part 84" 2355:

Spelce, David; Rehak, Timothy R; Meltzer, Richard W; Johnson, James S (2019).

600: 7254: 7011: 6968: 6927: 6820: 6803: 6761: 6474: 6025: 5994: 5615: 5360: 5330: 5240: 5161: 4235: 4186:"Protective gear in national stockpile is nearly depleted, DHS officials say" 4055: 3679: 3643: 3401: 3312: 3189: 3038: 2980: 2846: 2723: 2624: 1552: 1533: 1416:

However, separate from "barrier precautions" and "standard precautions" are "

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filtration of at least 95% under a 0.3 micrometer 200 milligram test load of

275: 255: 251: 161: 96: 5861: 3393: 3138:. U.S. Centers for Disease Control and Prevention. July 2019. pp. 55–56 2905:"Multi-Walled Carbon Nanotubes; Significant New Use Rule (40 CFR 721.10155)" 2197:"Respirator Trusted-Source Information | NPPTL | NIOSH | CDC" 2133:. U.S. National Institute for Occupational Safety and Health. March 19, 2020 1499:

A Hospital Corpsman wearing a Surgical N95 during the initial months of the

1248:, and other liquid-borne particles from the mouth and nose that may contain 7222: 7160: 6922: 6902: 6850: 6798: 6749: 6549: 6499: 6110: 5681: 5430: 5282: 5203: 5093: 4731: 4687: 4636: 4555: 4519: 4470: 4426: 4408: 4377: 4324: 4322: 4094: 4079: 4071: 3903: 3727: 3709: 3419: 3362: 3025: 2833: 2741: 2504: 2382: 1425: 1319: 1296: 1131: 1127: 1123: 971: 933: 913:

the respirator decreases the chances of airborne contamination by viruses.

538: 353: 235: 203: 80: 4305:"3M faces pressure from Trump order to stop exporting N95 masks to Canada" 4224:"It's Bedlam in the Mask Market, as Profiteers Out-Hustle Good Samaritans" 2547: 878:

Infographic on three key factors required for a respirator to be effective

7115: 6917: 6840: 6815: 6564: 6544: 6449: 6409: 6333: 5704: 5699: 5620: 5603: 5447: 5390: 5188: 5183: 5178: 5103: 5083: 4794:"Just One Human Is Infected by Bird Flu in the US. More Cases Are Likely" 4719: 3895: 3343: 3080:"Respirator Trusted-Source Information: Ancillary Respirator Information" 2811:"N95 Respirators, Surgical Masks, Face Masks, and Barrier Face Coverings" 2357:"History of U.S. Respirator Approval (Continued) Particulate Respirators" 1197: 906: 4319: 3995: 2580: 2336:"The Historic and Cultural Importance of the HAWKS NEST TUNNEL DISASTER" 1616: 928:

N95 respirators are also designed for industrial use in sectors such as

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interest; the actual data in that study showed that N95s were superior.

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Prior to the 1970s, respirator standards were under the purview of the

4830: 2879:"Respiratory Protection for Workers Handling Engineered Nanoparticles" 1293:

No Admittance Without Wearing a Type N95 or More Protective Respirator

348: 226:

The N95 standard does not require that the respirator be resistant to

7125: 6604: 5637: 5632: 5565: 5385: 5325: 5115: 4984: 4700: 4594:"Study on masks vs N95 respirators for health workers spurs concerns" 1249: 1152:, although caution should be exercised when considering this option. 959: 528: 438: 307: 211: 152:

Surgical N95 respirators for use in health care are both approved by

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N95 respirator and a surgical mask for prevention against the flu.

7108: 7023: 6599: 6574: 6527: 6072: 5642: 5585: 4945: 3815:"Update: Severe Acute Respiratory Syndrome --- United States, 2003" 2603:"Proper N95 Respirator Use for Respiratory Protection Preparedness" 2601:

D'Alessandro, Maryann M.; Cichowicz, Jaclyn Krah (March 16, 2020).

2399:. US Department of Labor, US Mine Safety and Health Administration. 1421: 1411: 1318:

proposed new rule changes for industries affected by the spread of

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Historically, respirators in the US had generally been approved by

832: 548: 92: 4825: 4532: 4439: 4354: 1391:

In 2007, the CDC HICPAC published a set of guidelines, called the

146: 59:(NIOSH) N95 standard of air filtration, filtering at least 95% of 6912: 6783: 6036: 3678:

This article incorporates text from this source, which is in the

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This article incorporates text from this source, which is in the

3502:

Schwartz, Antony; Stiegel, Matthew; Greeson, Nicole; et al.

3311:

This article incorporates text from this source, which is in the

3188:

This article incorporates text from this source, which is in the

2623:

This article incorporates text from this source, which is in the

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paper garnered a million views, while another retracted paper in

1463: 1189: 87:. Since then, N95 respirator has continued to be solidified as a 4391:

Klompas M, Pandolfi MC, Nisar AB, Baker MA, Rhee C (July 2022).

2069:"World Depends on China for Face Masks But Can Country Deliver?" 1520:

Face masks during the COVID-19 pandemic § N95 and FFP masks

1513: 1279:

Source control (respiratory disease) § US HIV/AIDS Epidemic

7120: 6685: 6338: 5934: 4746:"Key Public Health Prevention Recommendations for HPAI A(H5N1)" 2218:"Counterfeit Respirators / Misrepresentation of NIOSH-Approval" 2179:"Certified Equipment List | NPPTL | NIOSH | CDC" 2051:"Counterfeit Respirators / Misrepresentation of NIOSH Approval" 1681: 1580: 1548: 1377: 929: 676: 124: 100: 67:

of 0.3 micrometers under 42 CFR 84, effective July 10, 1995. A

3290:"Decontamination and Reuse of Filtering Facepiece Respirators" 2269:"Health Canada issues recall of some KN95 masks made in China" 6349: 4041:"Respirator or face mask? Best H1N1 protection still debated" 1931: 1668:

state officials to allow CDC investigators into dairy farms.

994:

2 and higher, respirators are recommended to be discarded as

909:

at the sealing area of the respirator will cause it to leak.

846: 267: 243: 153: 5563: 4483: 4158:. American Industrial Hygiene Association. January 20, 2022. 1952:

Face masks during the COVID-19 pandemic in the United States

5802: 4768:"Protect Yourself From H5N1 When Working With Farm Animals" 4110:"CDC finalizes flu prevention guidance for health settings" 2313:"Important safety information for certain respirator masks" 2004: 1638: 1315: 1288: 1283: 1144: 1083:

COVID-19 pandemic § Face masks and respiratory hygiene

869: 858:. Standards and specifications are also subject to change. 444: 263: 4649: 3876: 3462:

March 2020, Rafi Letzter – Staff Writer (March 24, 2020).

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