Asbestos Exposure Limits
PELs, TEVs, RELs & RBCs for Asbestos Exposure

Asbestos exposure limit regulations & recommendations from various governments & government agencies.

How to guess at the probable presence of asbestos-containing materials in a building.

This article provides definitions and actual numbers for recommended as well as regulated exposure limits to asbestos as provided by several U.S. agencies including the US EPA, NIOSH, and OSHA, by other countries' governments, and by professional associations such as ACGIH.

Asbestos Containing Materials Exposure Limits

Definition of Asbestos Containing Material

In the U.S. and other countries, using the U.S. EPA guidelines, if either TEM or PLM analysis yields a result that the asbestos-suspect material contains greater than 1 percent asbestos, then the material must be considered ACM - "Asbestos-Containing-Material" and thus would merit appropriate protective measures depending on the material's friability, condition and location. - U.S. EPA, ASBESTOS FREQUENTLY ASKED QUESTIONS [PDF] cited in the REFERENCES section of this article.

Really? In the U.S. OSHA regulations and letters clarifying them also state that items or materials that do not contain >1% asbestos are covered to at least some extent by the Construction Asbestos Standard.

That is, in the workplace, OSHA 29 CFR 1926.1101 would apply even if neither asbestos permissible exposure limit (PEL) is exceeded 1.

The standard contains numerous work practice requirements and prohibitions which apply, regardless of the exposure levels.

However, only two of the requirements and three of the prohibitions must be observed in the case of work activities involving installed construction materials that do not contain >1% asbestos. Details from OSHA are given later in this article.

That same US EPA reference and many others also remark that

Asbestos that is in good condition and left undisturbed is unlikely to present a health risk. The risks from asbestos occur when it is damaged or disturbed where asbestos fibers become airborne and can be inhaled.

Managing asbestos in place and maintaining it in good repair is often the best approach.

Illustration above: health data from inhalation exposure to asbestos fibers in air, exposure limits from various sources, provided by the U.S. EPA cited just below. [Click to enlarge any image]

What is the Permissible Exposure Limit (PELs) for Asbestos in or at Buildings?

Asbestos concentrations are reported as either fibers per mL air (fibers/mL) or fibers per cm³ air (number of asbestos fibers detected in one cubic centimer of air). Note that fibers / mL = fibers / cm3.

Beginning in 1986 OSHA set a permissible exposure limit (PEL) of 0.2 fibers per cubic centimeter (f/cc) of air over an 8-hour time-weighted average exposure period.

OSHA also set an action level of 0.1 f/cc of asbestos for an 8-hour TWA average, and (the highest permitted short term asbestos fiber exposure) 1.0 f/cc "excursion limit" for a 30-minute time period.

Thanks to reader Thomas Sukeforth for pointing out a 1994 summary of changes made to the OSHA Asbestos Construction standard and for suggesting a discussion of PACM (below).

The time-weighted average (TWA) permissible exposure limit has been reduced to 0.1 fibers per cubic centimeter. The Excursion Limit remains at 1.0 fibers per cubic centimeter averaged over 30 minutes. Both of these values are considered PELs. (permissible exposure limits).

There is no established action level in the new asbestos exposure standard because the sampling and analytical method is not reliable below the time-weighted average limit of 0.1 fibers per cubic centimeter.

The following is excerpted from 2016 U.S. EPA, ASBESTOS HAZARD SUMMARY 1332-21-4 (Updated), retrieved 2018/06/13, original source: https://www.epa.gov/sites/production/files/2016-10/documents/asbestos.pdf

Summary Recommended Asbestos Exposure Limits

Asbestos Toxicity or Health Risk Value

Health risk or RBC numbers are toxicological numbers from animal testing or risk assessment values developed by EPA.

Lifetime Asbestos RBC for a 1 in 10,000 cancer risk: 4 x 10^-4 fibers / cm³ (Reference 2 below)

Lifetime Asbestos RBC for a 1 in 1 million cancer risk: 4 x 10^-6 fibers / cm³ (Reference 2 below)

• RBC (Cancer risk-based concentration)--a calculated concentration of a chemical in air to which continuous exposure over a lifetime is estimated to be associated with a risk of contracting cancer not greater than the specified probability (e.g., 1 in 1 million).
• Definition of RBC: Risk Based Concentration

OSHA Asbestos PEL 0.1 fibers / cm³

• OSHA PEL--Occupational Safety and Health Administration's permissible exposure limit expressed as an 8-hour time-weighted average; the concentration of a substance to which most workers can be exposed without adverse effect averaged over a normal 8-h workday or a 40-h workweek.
• Definition of PEL: Permissible Exposure Limit: the legal limit (in the United States) for exposure of an employee to a chemical substance or physical agent (such as loud noise or particles of asbestos). PELs are set by OSHA, a U.S. government agency. OSHA PEL numbers are regulatory

NIOSH Asbestos REL 0.1 fibers / cm³

• NIOSH REL--National Institute of Occupational Safety and Health's recommended exposure limit;
  
  NIOSH-recommended exposure limit for asbestos fibers >5 micrometers in length. Additionally,
  
  NIOSH considers asbestos to be a potential occupational carcinogen and recommends that exposures be reduced to the lowest feasible concentration.
• Definition of REL: Recommended Exposure Limit or recommended exposure limit (REL) is an occupational exposure limit that has been recommended by NIOSH the United States National Institute for Occupational Safety and Health to the Occupational Safety and Health Administration (OSHA) for adoption as a permissible exposure limit.
  
  NIOSH REL numbers are advisory.

ACGIH Asbestos TLV 0.1 fibers / cm³

• ACGIH TLV--American Conference of Governmental and Industrial Hygienists' threshold limit value expressed as a time-weighted average; the concentration of a substance to which most workers can
  be exposed without adverse effects.
• Definition of TLV: Threshold Limit Value of a chemical substance is believed to be a level to which a worker can be exposed day after day for a working lifetime without adverse effects. TLV is a reserved term of the American Conference of Governmental Industrial Hygienists (ACGIH).
  
  ACGIH TLV numbers are advisory.

Definition of Asbestos Regulatory Value vs Advisory Value for Asbestos Exposure Limits

Regulatory exposure limit numbers are values that have been incorporated in Government regulations, while advisory numbers are nonregulatory values provided by the Government or other groups as advice.

References for Permissible Asbestos Exposure Limits

1. Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Asbestos. Public Health Service, U.S. Department of Health and Human Services, Atlanta, GA. 2001. http://www.atsdr.cdc.gov/ToxProfiles/tp61.pdf

2. U.S. Environmental Protection Agency. Integrated Risk Information System (IRIS) on Asbestos. National Center for Environmental Assessment, Office of Research and Development, Washington, DC. Last revised 9/26/1988. http://www.epa.gov/iris

3. National Toxicology Program (NTP). Report on Carcinogens, Thirteenth Edition. Research Triangle Park, NC: U.S. Department of Health and Human Services, Public Health Service. 2014. http://ntp.niehs.nih.gov/pubhealth/roc/roc13/

4. International Agency for Research on Cancer (IARC). IARC Monographs on the Evaluation of Carcinogenic Risks to Humans: Arsenic, Metals, Fibres, and Dusts. Volume 100C. World Health Organization, Lyon, France. 2012.
https://publications.iarc.fr/ENG/Monographs/vol100C/mono100C-11.pdf

5. National Institute for Occupational Safety and Health (NIOSH). Pocket Guide to Chemical Hazards. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention. Cincinnati, OH. 2015. http://www.cdc.gov/niosh/npg/

6. Occupational Safety and Health Administration (OSHA). Occupational Safety and Health Standards, Toxic and Hazardous Substances. Code of Federal Regulations. 29 CFR 1910.1000. 1998.
https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9 992&p_text_version=FALSE

7. American Conference of Governmental Industrial Hygienists (ACGIH). 2015 TLV's and BEIs. Threshold Limit Values for Chemical Substances and Physical Agents, Biological Exposure Indices. Cincinnati, OH.

OSHA Clarifications on Asbestos Handling & Exposure Regulations in Schools depending on the percentage of asbestos in a tested sample

Source: "Questions concerning the OSHA requirements covering the renovation of school buildings that have hard plaster containing some asbestos, but the amount is not more than 1%", [PDF], OSHA Clarification, (2003) cited atReferences or Citations

Question 1: Are the OSHA letters dated April 17, 1997; August 7, 1998; and August 13, 1999 correct? They all say that items that do not contain >1% asbestos are covered to at least some extent by the Construction Asbestos Standard.

Reply: Yes, those letters are correct although some requirements of the Construction Asbestos Standard, 29 CFR 1926.1101 were not addressed. 29 CFR 1926.1101 would apply even if neither asbestos permissible exposure limit (PEL) is exceeded1.

The standard contains numerous work practice requirements and prohibitions which apply, regardless of the exposure levels. However, only two of the requirements and three of the prohibitions must be observed in the case of work activities involving installed construction materials that do not contain >1% asbestos.

Those work practice requirements and prohibitions that must be observed regardless of the exposure levels and of the percentage of asbestos in the installed construction materials are:

29 CFR 1926.1101(g)(1)(ii), which requires: wet methods, or wetting agents, to control employee exposures during asbestos handling, mixing, removal, cutting, application, and cleanup, except where employers demonstrate that the use of wet methods is infeasible due to, for example, the creation of electrical hazards, equipment malfunction, and, in roofing, except as provided in paragraph (g)(8)(ii)2 of this section;

29 CFR 1926.1101(g)(1)(iii), which requires: prompt clean-up and disposal of wastes and debris contaminated with asbestos in leak-tight containers except in roofing operations, where the procedures specified in paragraph (g)(8)(ii)3 of this section apply;

29 CFR 1926.1101(g)(3)(i), which prohibits: high-speed abrasive disc saws that are not equipped with point-of-cut ventilator or enclosures with HEPA filtered exhaust air;

29 CFR 1926.1101(g)(3)(ii), which prohibits: compressed air used to remove asbestos, or materials containing asbestos, unless the compressed air is used in conjunction with an enclosed ventilation system designed to capture the dust cloud created by the compressed air; and

29 CFR 1926.1101(g)(3)(iv), which prohibits: employee rotation as a means of reducing employee exposure to asbestos.

There are also some other provisions that apply to work activities involving installed construction materials even where the material does not contain >1% asbestos. However, if neither asbestos PEL is exceeded, only the following few provisions apply:

29 CFR 1926.1101(f)(2)(i), the provision for establishing that neither asbestos PEL is exceeded:

Each employer who has a workplace or work operation covered by this standard shall ensure that a "competent person" conducts an exposure assessment immediately before or at the initiation of the operation to ascertain expected exposures during that operation or workplace.

The assessment must be completed in time to comply with requirements which are triggered by exposure data or the lack of a "negative exposure assessment," and to provide information necessary to assure that all control systems planned are appropriate for that operation and will work properly;

29 CFR 1926.1101(f)(6)(i), a provision covering the observation of monitoring:

The employer shall provide affected employees and their designated representatives an opportunity to observe any monitoring of employee exposure to asbestos conducted in accordance with this section;

29 CFR 1926.1101(f)(5)(i), a provision covering employee notification of monitoring results:

The employer shall notify affected employees of the monitoring results that represent that employee's exposure as soon as possible following receipt of monitoring results;

29 CFR 1926.1101(f)(5)(ii), another provision covering employee notification of monitoring results:

he employer shall notify affected employees of the results of monitoring representing the employee's exposure in writing either individually or by posting at a centrally located place that is accessible to affected employees; and

29 CFR 1926.1101(n)(2)(i)-(iii), a set of provisions covering recordkeeping for measurements of exposures to airborne asbestos.

There are numerous additional provisions of the standard that apply to work activities involving installed construction materials even where the material does not contain >1% asbestos if at least one of the asbestos PELs is exceeded.

...

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Question: how can I find out what asbestos-containing-materials were in my work-place built in the 1920s?

I am trying to find out what the name of the products used in the building where I worked for two decades.

The building was constructed in a major U.S. city in 1926 Floor tiles, insulation, plumbing, etc.
Any idea where I can find this information?

During the time of my employment there were several asbestos abatement jobs carried out on or in my building, but I was never told about them at the time. Now I suffer from lung cancer diagnosed as mesothelioma. - Anonymous by private email 2022/06/02

Moderator reply:

OPINION: where there is big money and liability involved, it's no surprise to run into a stone wall. It's cheaper for an institution or company to pay lawyers to fight until a plaintiff dies than to engage in a big settlement to cover that person's care and losses.

And to be a bit careful, while at-work exposure could indeed be a source of mesothelioma, it's not the only possible cause.

1920s - 1980s building materials that may have contained asbestos

It would be unusual to find detailed building material records from a building constructed so long ago, but the records of exactly what asbestos abatement operations were done, their location, their scope, pre- and post- work inspections and test results would certainly have existed and ought to be able to be obtained through an attorney.

Also, don't assume that only 1920s building materials contained asbestos. Asbestos was used in thousands of products up into the mid 1980s in the U.S. and still later in some other countries, as explain

at ASBESTOS MATERIAL REGULATIONS.

A few materials (I'll give an example below) can be reliably identified as asbestos-containing-material (ACM) from photos, while others can be reliably identified based on combination of age and appearance (such as asbestos cement board)

Still other asbestos-suspect materials would have had to be tested.

If also in historical records one could obtain photographs of the building interior taken during the time that you worked there, we could at least rule some materials or topics in or out as possible asbestos-containing-material (ACM).

• Floors: For example if we see 9x9 asphalt floor tile, virtual all of that will have contained asbestos, as did much 9x9 vinyl- and some 12x12- vinyl floor tile and some sheet flooring installed any time up to about 1986.
• Ceilings: Ceiling tiles are more-difficult to classify from photos alone as there were some brands that never used asbestos.
• Paints: Acoustic paints, textured paints, popcorn ceiling paint, and some fire-resistant materials certainly made wide use of asbestos.

• Insulation: Some pipe insulation such as on heating pipes, made of corrugated asbestos paper, is an example of a material that can be identified as virtually certain to have used asbestos as there were no non-asbestos look-alikes.
  
  See ASBESTOS PIPE INSULATION
• Window putty and other maintenance materials, sealants, etc. may have contained asbestos, again with a level of hazard that varies significantly depending on the material's location, condition, and disturbance.
• We provide a photo-guide to asbestos- or asbestos-suspect materials
  
  at MOST COMMON OCCURRENCES OF ASBESTOS IN BUILDING and

  at ASBESTOS PHOTO GUIDE to MATERIALS

  and a near-exhaustive list

  at ASBESTOS PRODUCING COMPANIES & TRUSTS

Exposure to asbestos in the building where you worked

The EPA has concluded that the presence of asbestos materials in the workplace can be a hazard to workers. But it's worth a cautious look and one should avoid panic - which itself is a health hazard.

Non-friable materials in good condition, such as floor tiles, even if they contained asbestos, would not be likely to explain asbestos-related illness unless they were damaged or demolished making a dusty mess without proper protective measures.

Even friable materials in good condition, such as asbestos pipe insulation, would not explain a high level of airborne asbestos dust in a building unless damaged similarly as I just noted.

If asbestos removal work or "abatements" were conducted improperly that could indeed create a hazard for building occupants.

Building conditions such as mechanical systems that circulate air, building maintenance and repair work (not just asbestos removal projects) and similar activities could also affect the condition of or cause damage to ACM.

Who investigates the history of asbestos in the building where you worked?

If your attorney is simply telling you to do the work then my opinion of that counsel is rather low. Rather than argue with such I'd find someone else.

I'd expect the attorney to also determine what legal notification of asbestos abatement would have been required (eg by OSHA and or the US EPA) to be provided to people working in the building during such activity.

If your workplace was in the United States, this link will illustrate what the US EPA and OSHA have to say

about WORKER NOTIFICATION of PRESENCE of ASBESTOS or ASBESTOS REMEDIATION - Building owners should inform occupants about the presence of ACM

On 2020-07-09 by (mod)- EPA recently concluded that current uses of asbestos in the U.S. pose a significant risk to workers and bystanders

Re-posting:

The U.S. EPA recently concluded that current uses of asbestos in the U.S. pose a significant risk to workers and bystanders supporting the need for a ban on importing, exporting, manufacturing, and using all asbestos-containing materials. In March, EPA released its Draft Risk Evaluation for Asbestos under the Toxic Substances Control Act (TSCA) review of the current uses of asbestos in the U.S.

This action followed the prioritization of asbestos as one of the top 10 toxic substances to be reviewed under this new provision. As envisioned, this is a first step in implementing additional regulations or controls.


However, the draft document has multiple deficiencies and is far from comprehensive in failing to account for all forms of asbestos, all uses of asbestos, and asbestos that is present in millions of homes, buildings and other structures. EPA indicated that they plan to address legacy uses of asbestos and waste disposal in a separate document.

Source: Occupational Knowledge International Newsletter, July 2020 Website: www.okinternational.org

Question: how do you dispose of asbestos in Sweden

(June 29, 2014) sandra said:
how do you dispose of asbestos in sweden is it costly

Reply:

Quoting from EU regulations and data

Asbestos - Training and permits are mandatory

There are common EU rules determining provisions concerning asbestos. The provisions apply to all activities where there is a risk that an employee will be exposed to the dust which contains asbestos. To work with asbestos, you need a special permit from the Swedish Work Environment Authority, you also need training as well as a medical examination certificate.

A company that conducts demolition work on materials that contain asbestos without permission from the Swedish Work Environment Authority risks having to pay a penalty of SEK 50,000. Questions regarding products that contain asbestos are covered by the Chemicals Agency’s regulations.

This is where you can read the entire provision on asbestos

www.av.se/dokument/inenglish/legislations/eng0601.pdf

...

Continue reading at ASBESTOS MATERIAL REGULATIONS or

see EPA ASBESTOS MATERIAL REGULATIONS - 1999 Update that includes more recent asbestos regulations for the U.S. and other countries. That article clarifies just what products are currently permitted or not permitted to contain asbestos. - or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• ASBESTOS DISPOSAL REGULATIONS
• ASBESTOS IDENTIFICATION IN BUILDINGS - home
• ASBESTOS MATERIAL REGULATIONS
  • HISTORY & DATES OF ASBESTOS CONTAINING MATERIAL BANS & REGULATIONS
  • COUNTRIES THAT BAN OR REGULATE THE USE OR PRODUCTION OF ASBESTOS
  • DEFINITION OF & HANDLING RULES FOR SUSPECT ASBESTOS CONTAINING MATERIALS (SACM)
  • DEFINITION OF & HANDLING RULES FOR PRESUMED ASBESTOS CONTAINING MATERIAL (PACM)
  • ASBESTOS EXPOSURE LIMITS (PELS) TLVs RBCs & RELs
  • MOST COMMON OCCURRENCES OF ASBESTOS IN BUILDING
  • WORKER NOTIFICATION of PRESENCE of ASBESTOS or ASBESTOS REMEDIATION
• ASBESTOS REMOVAL, WETTING GUIDELINES
• ASBESTOS ROOF MATERIALS
• CANADA ASBESTOS REGULATIONS
• U.K. ASBESTOS REGULATIONS

Suggested citation for this web page

ASBESTOS EXPOSURE LIMITS (PELS) TLVs RBCs & RELs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to ASBESTOS HAZARDS

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Citations & References

In addition to any citations in the article above, a full list is available on request.