AHERA Asbestos Supervisor key terms

The tendency of certain minerals to crystallize as long, thin, flexible fibers rather than as blocky grains. This fibrous growth habit is what allows asbestos to be woven, sprayed, and easily inhaled.

A mineral group whose only regulated asbestiform member is chrysotile, a curly white fiber. Chrysotile accounts for most asbestos used commercially in buildings and is the type most often found in pipe insulation and floor tile.

The asbestiform variety of serpentine, consisting of soft, curly, easily bent fibers. It resists heat and was widely used in insulation, cement products, and friction materials, and it is the most common asbestos type encountered in buildings.

A group of straight, needle-like asbestiform minerals including amosite, crocidolite, anthophyllite, tremolite, and actinolite. Their straighter, stiffer fibers are generally considered more hazardous and more persistent in lung tissue than chrysotile.

A brownish amphibole asbestos once used in pipe insulation and ceiling tiles. Its straight, brittle fibers are linked to high rates of mesothelioma and asbestosis among exposed workers.

A blue amphibole asbestos known as the most carcinogenic fiber type. It was used in some cements, sprays, and insulation, and its presence raises the health concern level of any project.

The ability of a fiber to reach the deep lung, generally associated with fibers that are long, thin, and durable enough to avoid being cleared. Fibers roughly longer than 5 micrometers and thinner than 3 micrometers are of greatest concern.

A progressive, irreversible scarring of lung tissue caused by inhaling asbestos fibers. It typically follows years of heavy exposure and causes shortness of breath, cough, and reduced lung function.

A rare cancer of the thin membrane lining the lungs or abdominal cavity, strongly associated with asbestos exposure. It has a long latency period, often decades, and can occur after relatively low exposures.

The delay between first asbestos exposure and the appearance of disease, commonly 10 to 40 years. Because of this delay, current illnesses reflect exposures that occurred many years earlier.

An air pollutant listed under the Clean Air Act for which short-term exposure can cause serious harm. Asbestos is regulated as both a hazardous air pollutant and an acute hazardous air pollutant under the national emission standards.

The National Emission Standards for Hazardous Air Pollutants, the federal Clean Air Act rules that govern asbestos work in demolition and renovation. They set work practice, notification, and waste-handling requirements enforced by the EPA.

Under NESHAP, material containing more than one percent asbestos by weight that is friable, or that will become friable during handling. This threshold determines when federal work practice standards apply.

A written notice that must be given to the appropriate EPA or state authority before demolition or renovation of a facility with regulated asbestos material above threshold amounts. It identifies the owner, contractor, quantities, and scheduled dates.

Material that can be crumbled, pulverized, or reduced to powder by hand pressure when dry. Friable asbestos is the greatest release risk and is subject to the strictest handling rules.

Nonfriable asbestos-containing material such as packings, gaskets, resilient floor coverings, and asphalt roofing products. It is regulated differently from friable material because fibers are bound in a matrix.

Nonfriable asbestos-containing material other than Category I, such as some cement products, that is more likely to become friable when disturbed. It may be treated as regulated material depending on how it is handled.

The Asbestos Hazard Emergency Response Act, which requires schools to inspect for asbestos, prepare management plans, and use accredited personnel for inspection and abatement. It also established the model accreditation program that many states adopted.

The credential a person earns by completing an approved training course and passing a written exam, such as the supervisor or worker accreditation required by AHERA. It must be renewed periodically through refresher training.

Periodic retraining required to keep an asbestos accreditation valid, typically an annual course for supervisors and workers. It updates regulations, work practices, and safety information.

A test that verifies a respirator seals against a specific wearer's face, using either qualitative methods such as saccharin or quantitative methods such as a portacount. It must be repeated at least annually and whenever facial conditions change.

A numerical ratio comparing the concentration of a test agent outside a respirator to the concentration inside it. Higher fit factors indicate a better seal and are used in quantitative fit testing.

A pass/fail fit test that uses a detectable taste or odor agent, such as saccharin, Bitrex, or irritant smoke, to check for leakage. It is used for negative-pressure respirators and does not produce a numeric fit factor.

A fit test that measures actual leakage with an instrument and reports a numeric fit factor. It is required for full-facepiece and powered air-purifying respirators in many programs.

The level of protection a properly fitted respirator class is expected to provide, expressed as the ratio of outside to inside concentration. Supervisors use it to select a respirator adequate for the measured or expected exposure level.

A negative-pressure respirator covering the nose and mouth with a typical assigned protection factor of 10. It is commonly used with high-efficiency particulate filters for asbestos work at lower exposure levels.

A high-efficiency particulate air filter rated to remove at least 99.97 percent of particles 0.3 micrometers in diameter. It is required on respirators, vacuums, and negative air machines used in asbestos abatement.

A confidential health review, often a questionnaire, that a physician or other licensed health care professional uses to determine whether an employee can safely wear a respirator. It must precede fit testing and respirator use.

A sealed enclosure of plastic sheeting and framing built around the work area to prevent fiber release. It includes critical barriers over openings, negative pressure, and a decontamination unit at the entry.

A HEPA-filtered exhaust unit that keeps the containment under negative pressure so air flows inward and fibers do not escape. Units are sized to provide roughly four air changes per hour and must run continuously.

A temporary seal, usually plastic sheeting, placed over openings such as doors, windows, and vents that could allow air to bypass the containment. It ensures the only air path is through the negative air filtration.

A sequence of connected rooms through which workers pass when leaving the work area: a dirty room, a shower, and a clean room. It removes fibers from people and equipment before they exit.

The final stage of the decontamination unit, where clean clothing is stored and put on after showering. No contaminated person or material may enter it.

The first stage of the decontamination unit, where workers remove contaminated clothing and equipment before entering the shower. It is considered part of the contaminated work area.

The required routine of showering and changing before leaving the site, keeping street clothes separate, and never eating, drinking, or smoking in the work area. It prevents fibers from being carried home.

Contamination carried from the workplace on clothing, skin, or hair to family members at home. Strict decontamination and separate work clothing prevent this secondary exposure.

Collection of air samples from fixed locations to measure fiber concentrations in or near a work area. It is used to verify containment integrity and to document background levels.

Sampling with a pump and filter worn in the worker's breathing zone to measure that worker's exposure. Results are compared with permissible exposure limits and used to select respirators.

The standard laboratory method for counting airborne fibers on a membrane filter. It counts all fibers meeting size criteria, not just asbestos, so it is a screening rather than a definitive identification method.

A small piece of suspect material collected for laboratory analysis to determine asbestos content and type. Proper sampling avoids disturbing the material and prevents fiber release.

A laboratory technique that identifies asbestos minerals in bulk samples by their optical properties. It is the standard method for determining whether building material contains asbestos.

Post-abatement air sampling inside the containment to confirm that fiber levels are low enough for the area to be reoccupied and the containment removed. It must meet the project's stated criterion before teardown.

The legally enforceable limit on airborne contaminant concentration in the workplace, set by OSHA. For asbestos it is expressed as fibers per cubic centimeter averaged over an eight-hour shift.

An exposure measure that averages concentrations over a defined period, typically eight hours, to reflect a full work shift. It accounts for varying exposure levels during the day.

A required program of health monitoring for employees exposed above specified levels, including medical history, physical exam, and sometimes chest imaging. Records must be kept and made available to the employee.

Documentation of an employee's measured airborne exposures, kept for decades and provided to the worker on request or at termination. It supports medical surveillance and future claims.

Material that is treated as containing asbestos until sampling proves otherwise, often because of its age or typical composition. Treating it as contaminated protects workers when testing is unavailable.

The written project requirements describing scope, methods, materials, and performance standards for an abatement job. The supervisor must build the work plan to meet these requirements and document compliance.

The supervisor's detailed written description of how the abatement will be performed, including containment design, sequencing, staffing, and safety measures. It translates contract specifications into site instructions.

A written modification to the contract scope, schedule, or price approved after the original agreement. Supervisors must document changed conditions, such as unexpected asbestos, before performing extra work.

The coverage and legal responsibility an abatement contractor carries for worker injury, property damage, and pollution incidents. Supervisors should confirm coverage types and limits before work begins.

Records proving each worker completed required asbestos training and holds a valid accreditation. Supervisors verify these before allowing anyone into the containment.