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The Asbestos Standard, 29 CFR 1910.1001

Initially used by the ancient Greeks who spun it into a cloth-like material, asbestos is a naturally occurring mineral that's been known to man for centuries. In modern times, asbestos first became widely used during the industrial revolution by manufacturers who valued both its structural strength and insulating properties.

The popularity of asbestos escalated during the early to mid 20th century. By the 1930s asbestos was known as the "miracle mineral," and it was used in everything from insulation and fire walls, to Christmas tree ornamentation. As the century progressed, sprayed asbestos fireproofing materials were incorporated into new building construction. It's estimated that half of the multi-story buildings constructed during the '50s-'70s contain some form of sprayed asbestos containing materials.

During the late '60s, evidence began to emerge that removed some of the luster from this miracle mineral. Studies were indicating that asbestos presented a health risk. By the '70s, the federal government began to regulate asbestos, and OSHA's Asbestos Standard, 29 CFR 1910.1001, was published June 20th. 1986.

With the information now available concerning the dangers associated with asbestos, it's vital for those exposed to have an awareness of the health hazards it presents. Knowledge of air monitoring methods and appropriate personal protective equipment is also important for employees working with asbestos.

Health Hazards

The human respiratory system has basic mechanisms to filter the air we breathe. However, even with our natural defenses at work, some particulate material does pass through and reach the lung wall. Once attached to the lung wall, most particles are attacked and destroyed by large cells called macrophages. Because asbestos is a mineral fiber, the macrophages are unable to remove it from the lung. The macrophages deposit a coating on the asbestos fiber, and scar tissue begins to form around it.

Asbestosis, lung cancer, and mesothelioma are three diseases associated with asbestos exposure. Asbestosis is characterized by fibrotic scarring of the lung. It's a restrictive lung disease that reduces lung capacity. Asbestosis is prevalent among workers who have been exposed to large doses of asbestos over a long period of time.

Studies indicate that employees exposed to industrial concentrations of asbestos have an increased risk of lung cancer. This risk is compounded for smokers who work with asbestos. Mesothelioma is a cancer of the chest cavity lining. It's the rarest of the three asbestos-related diseases.

It's important to note that the studies that have documented the hazards of asbestos were conducted with asbestos workers and laboratory animals. Risks associated with low level, non-occupational exposures are not well established.

In terms of how much asbestos is too much, OSHA has established an eight-hour time-weighted average (TWA) permissible exposure limit (PEL) for employees of 0.1 fiber per cubic centimeter of air. They've also established a 30 minute excursion limit of 1.0 fiber per cubic centimeter (1 f/cc). The excursion limit is essentially a short-term exposure limit. Employees cannot be exposed to concentrations of asbestos exceeding 1 f/cc averaged over a 30 minute sampling period.

Employers with employees exceeding these exposure levels need to implement engineering or work practice controls to reduce the exposures below the established limits. If these controls are not feasible or can't by themselves reduce the exposures to acceptable levels, then respiratory protection, protective clothing and other personal protective equipment (PPE) must be implemented.

Monitoring for Asbestos

Appendix A in OSHA's Asbestos Standard identifies the mandatory protocol for conducting asbestos air monitoring. A continuous flow pump capable of delivering a flow rate of between 0.5 and 2.5 liters per minute is required. The sampling medium must be a mixed cellulose ester filter membrane, designated by the manufacturer as suitable for asbestos counting.

The appendix also states, "The preferred collection device shall be a 25-mm electrically conductive extension cowl. The 37-mm cassette may be used if necessary but only if written justification for the need to use the 37-mm filter cassette accompanies the sample results in the employees exposure monitoring record."

Once the samples are collected, they must be analyzed-the asbestos particles physically counted-by an analytical laboratory. The protocol the laboratory must follow is also detailed in Appendix A.

Respiratory Protection and PPE

Should the results of the monitoring determine that the exposure limits are being exceeded, the employer must implement engineering controls and work practices to reduce the exposure to acceptable levels. Improved ventilation or a reduction of the amount of dust created are examples of these control measures.

From an OSHA perspective, respiratory protection is the last option to reduce asbestos exposure. The following is the respirator selection guide found in OSHA's Asbestos Standard:

The "high efficiency filters" identified in the selection guide were for many years known as High Efficiency Particulate Absolute (HEPA) filters. With the adoption of NIOSH's 42 CFR 84 standard for particulate filters, 100 class filters will soon be the standard air purifying element for asbestos. Both HEPA and 100 Class filters are acceptable for asbestos. However, it's important to note that OSHA excludes any type of disposable respirator-even HEPA and 100 Class disposables-for asbestos protection.

Under 29 CFR 1910.1001(h), OSHA identifies protective clothing and equipment. Protective clothing is necessary to keep asbestos fibers from contacting the body, as well as to prevent the contamination of an employee's street clothes. Contaminated street clothing presents an obvious concern because asbestos fibers can be transported on the clothing from the work site to the employee's home.

In terms of appropriate PPE, OSHA suggests coveralls, gloves, head coverings, foot coverings, face shields and vented goggles. A Tyvek full-body coverall with elastic wrists, attached hood and booties, combined with nitrile gloves and ANSI-compliant face shield and goggles are specific examples of the PPE OSHA suggests.

Other PPE such as hard hats and steel-toed footwear may also be necessary depending upon the job function. For guidance selecting PPE specific to your application, contact Lab Safety Supply's Safety TECHline by calling (800) 356-2501 or visit our website at www.lss.com.

REFERENCES:

Code of Federal Regulations, Title 29, Part 1910.1001 (OSHA Asbestos Exposure Regulations)

Code of Federal Regulations, Title 40, Part 763 (EPA Asbestos Abatement Regulations)

"Asbestos Worker Manual," '95 edition. Good Armstrong & Associated, Ltd. Health & Safety Training Consultants. 2142 South 55th Street, Milwaukee, WI 53219, (414) 645-7600

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