Asbestos scope, definitions, classes of work and exposure limits study guide
29 CFR 1926.1101 is OSHA's asbestos standard for construction. This guide sets out what the federal rule text states in paragraphs (a) through (d): which work the section covers and the materials it does not apply to, the definitions of ACM, PACM, surfacing material and thermal system insulation, the four classes of asbestos work, terms such as disturbance, removal and repair, regulated areas and decontamination rooms, the competent person, the two permissible exposure limits and their averaging basis, and the duties of employers and general contractors on multi-employer worksites. goraedu is not an accredited training provider, and this is not a course or accreditation exam. Your State may run its own OSHA-approved plan with its own rules, so check them too. Every point links to the regulation and quotes its exact words.
Scope and application
29 CFR 1926.1101 regulates asbestos exposure in all work as defined in 29 CFR 1910.12(b). The list of covered activities that follows is not complete.
“This section regulates asbestos exposure in all work as defined in 29 CFR 1910.12(b), including but not limited to the following:”
Covered work includes demolition or salvage of structures where asbestos is present.
“Demolition or salvage of structures where asbestos is present;”
Covered work includes removal or encapsulation of materials containing asbestos.
“Removal or encapsulation of materials containing asbestos;”
Covered work includes construction, alteration, repair, maintenance, or renovation of structures, substrates, or portions of them that contain asbestos.
“Construction, alteration, repair, maintenance, or renovation of structures, substrates, or portions thereof, that contain asbestos;”
Transportation, disposal, storage, containment of and housekeeping activities involving asbestos or products containing asbestos are covered when they take place on the site or location at which construction activities are performed.
“Transportation, disposal, storage, containment of and housekeeping activities involving asbestos or products containing asbestos, on the site or location at which construction activities are performed.”
Coverage under the standard shall be based on the nature of the work operation involving asbestos exposure.
“Coverage under this standard shall be based on the nature of the work operation involving asbestos exposure.”
The section does not apply to asbestos-containing asphalt roof coatings, cements and mastics.
“This section does not apply to asbestos-containing asphalt roof coatings, cements and mastics.”
Not covered here
Two other activities named in 1926.1101(a), installation of products containing asbestos and asbestos spill/emergency cleanup, do not have their own points here; read paragraph (a) for the full list. We only write what an official source states, so study these parts with your certifying program's materials.
ACM, PACM and material categories
For purposes of the standard, "asbestos" includes PACM.
“For purposes of this standard, “asbestos” includes PACM, as defined below.”
Asbestos-containing material (ACM) means any material containing more than one percent asbestos.
“Asbestos-containing material (ACM), means any material containing more than one percent asbestos.”
PACM (presumed asbestos containing material) means thermal system insulation and surfacing material found in buildings constructed no later than 1980. The PACM designation may be rebutted under paragraph (k)(5).
“PACM means “presumed asbestos containing material”. Presumed Asbestos Containing Material means thermal system insulation and surfacing material found in buildings constructed no later than 1980. The designation of a material as “PACM” may be rebutted pursuant to paragraph (k)(5) of this section.”
Surfacing material means material that is sprayed, troweled-on or otherwise applied to surfaces, such as acoustical plaster on ceilings and fireproofing materials on structural members, or other materials on surfaces for acoustical, fireproofing, and other purposes.
“Surfacing material means material that is sprayed, troweled-on or otherwise applied to surfaces (such as acoustical plaster on ceilings and fireproofing materials on structural members, or other materials on surfaces for acoustical, fireproofing, and other purposes).”
Surfacing ACM means surfacing material which contains more than 1% asbestos.
“Surfacing ACM means surfacing material which contains more than 1% asbestos.”
Thermal system insulation (TSI) means ACM applied to pipes, fittings, boilers, breeching, tanks, ducts or other structural components to prevent heat loss or gain.
“Thermal system insulation (TSI) means ACM applied to pipes, fittings, boilers, breeching, tanks, ducts or other structural components to prevent heat loss or gain.”
Thermal system insulation ACM is thermal system insulation which contains more than 1% asbestos.
“Thermal system insulation ACM is thermal system insulation which contains more than 1% asbestos.”
A homogeneous area is an area of surfacing material or thermal system insulation that is uniform in color and texture.
“Homogeneous area means an area of surfacing material or thermal system insulation that is uniform in color and texture.”
Not covered here
How PACM is rebutted under paragraph (k)(5) is not covered in this set. We only write what an official source states, so study these parts with your certifying program's materials.
Classes of asbestos work
Class I asbestos work means activities involving the removal of TSI and surfacing ACM and PACM.
“Class I asbestos work means activities involving the removal of TSI and surfacing ACM and PACM.”
Class II asbestos work means activities involving the removal of ACM which is not thermal system insulation or surfacing material.
“Class II asbestos work means activities involving the removal of ACM which is not thermal system insulation or surfacing material.”
Class II work includes, but is not limited to, the removal of asbestos-containing wallboard, floor tile and sheeting, roofing and siding shingles, and construction mastics.
“This includes, but is not limited to, the removal of asbestos-containing wallboard, floor tile and sheeting, roofing and siding shingles, and construction mastics.”
Class III asbestos work means repair and maintenance operations where ACM, including TSI and surfacing ACM and PACM, is likely to be disturbed.
“Class III asbestos work means repair and maintenance operations, where “ACM”, including TSI and surfacing ACM and PACM, is likely to be disturbed.”
Class IV asbestos work means maintenance and custodial activities during which employees contact but do not disturb ACM or PACM.
“Class IV asbestos work means maintenance and custodial activities during which employees contact but do not disturb ACM or PACM”
Class IV work also covers activities to clean up dust, waste and debris resulting from Class I, II, and III activities.
“activities to clean up dust, waste and debris resulting from Class I, II, and III activities.”
Not covered here
The work practices and controls required for each class of work (paragraph (g)) are not covered in this set. We only write what an official source states, so study these parts with your certifying program's materials.
Work terms: disturbance, removal and repair
Disturbance means activities that disrupt the matrix of ACM or PACM, crumble or pulverize ACM or PACM, or generate visible debris from ACM or PACM.
“Disturbance means activities that disrupt the matrix of ACM or PACM, crumble or pulverize ACM or PACM, or generate visible debris from ACM or PACM.”
Under the definition of disturbance, in no event shall the amount of ACM or PACM so disturbed exceed what can be contained in one glove bag or waste bag, which shall not exceed 60 inches in length and width.
“In no event shall the amount of ACM or PACM so disturbed exceed that which can be contained in one glove bag or waste bag which shall not exceed 60 inches in length and width.”
Aggressive method means removal or disturbance of building material by sanding, abrading, grinding or other method that breaks, crumbles, or disintegrates intact ACM.
“Aggressive method means removal or disturbance of building material by sanding, abrading, grinding or other method that breaks, crumbles, or disintegrates intact ACM.”
Intact means that the ACM has not crumbled, been pulverized, or otherwise deteriorated so that the asbestos is no longer likely to be bound with its matrix.
“Intact means that the ACM has not crumbled, been pulverized, or otherwise deteriorated so that the asbestos is no longer likely to be bound with its matrix.”
Removal means all operations where ACM and/or PACM is taken out or stripped from structures or substrates, and it includes demolition operations.
“Removal means all operations where ACM and/or PACM is taken out or stripped from structures or substrates, and includes demolition operations.”
Repair means overhauling, rebuilding, reconstructing, or reconditioning of structures or substrates, including encapsulation or other repair of ACM or PACM attached to structures or substrates.
“Repair means overhauling, rebuilding, reconstructing, or reconditioning of structures or substrates, including encapsulation or other repair of ACM or PACM attached to structures or substrates.”
Demolition means the wrecking or taking out of any load-supporting structural member and any related razing, removing, or stripping of asbestos products.
“Demolition means the wrecking or taking out of any load-supporting structural member and any related razing, removing, or stripping of asbestos products.”
For paragraph (g)(6), omitting a procedure or component, or reducing or diminishing the stringency or strength of a material or component of the control system, is not a "modification".
“Omitting a procedure or component, or reducing or diminishing the stringency or strength of a material or component of the control system is not a “modification” for purposes of paragraph (g)(6) of this section.”
Regulated areas, barriers and decontamination
A regulated area is an area established by the employer to demarcate areas where Class I, II, and III asbestos work is conducted, and any adjoining area where debris and waste from that work accumulate.
“Regulated area means: an area established by the employer to demarcate areas where Class I, II, and III asbestos work is conducted, and any adjoining area where debris and waste from such asbestos work accumulate;”
A regulated area is also a work area within which airborne concentrations of asbestos exceed, or there is a reasonable possibility they may exceed, the permissible exposure limit. Requirements for regulated areas are in paragraph (e).
“and a work area within which airborne concentrations of asbestos, exceed or there is a reasonable possibility they may exceed the permissible exposure limit. Requirements for regulated areas are set out in paragraph (e) of this section.”
A critical barrier is one or more layers of plastic sealed over all openings into a work area, or any other similarly placed physical barrier, sufficient to prevent airborne asbestos in a work area from migrating to an adjacent area.
“Critical barrier means one or more layers of plastic sealed over all openings into a work area or any other similarly placed physical barrier sufficient to prevent airborne asbestos in a work area from migrating to an adjacent area.”
A decontamination area is an enclosed area adjacent and connected to the regulated area, consisting of an equipment room, shower area, and clean room, used for the decontamination of workers, materials, and equipment that are contaminated with asbestos.
“Decontamination area means an enclosed area adjacent and connected to the regulated area and consisting of an equipment room, shower area, and clean room, which is used for the decontamination of workers, materials, and equipment that are contaminated with asbestos.”
A clean room is an uncontaminated room having facilities for the storage of employees' street clothing and uncontaminated materials and equipment.
“Clean room means an uncontaminated room having facilities for the storage of employees' street clothing and uncontaminated materials and equipment.”
The equipment room (change room) is a contaminated room located within the decontamination area that is supplied with impermeable bags or containers for the disposal of contaminated protective clothing and equipment.
“Equipment room (change room) means a contaminated room located within the decontamination area that is supplied with impermeable bags or containers for the disposal of contaminated protective clothing and equipment.”
A glovebag is not more than a 60 × 60 inch impervious plastic bag-like enclosure affixed around an asbestos-containing material, with glove-like appendages through which material and tools may be handled.
“Glovebag means not more than a 60 × 60 inch impervious plastic bag-like enclosure affixed around an asbestos-containing material, with glove-like appendages through which material and tools may be handled.”
Not covered here
The requirements that apply inside regulated areas (paragraph (e)) and the decontamination and hygiene requirements (paragraph (j)) are not covered in this set. We only write what an official source states, so study these parts with your certifying program's materials.
Competent person and other roles
Beyond the definition in 29 CFR 1926.32(f), a competent person is one who is capable of identifying existing asbestos hazards in the workplace and selecting the appropriate control strategy for asbestos exposure, and who has the authority to take prompt corrective measures to eliminate them.
“Competent person means, in addition to the definition in 29 CFR 1926.32 (f), one who is capable of identifying existing asbestos hazards in the workplace and selecting the appropriate control strategy for asbestos exposure, who has the authority to take prompt corrective measures to eliminate them,”
For Class I and Class II work, the competent person is also specially trained in a training course which meets the criteria of EPA's Model Accreditation Plan (40 CFR part 763) for supervisor, or its equivalent.
“for Class I and Class II work who is specially trained in a training course which meets the criteria of EPA's Model Accreditation Plan (40 CFR part 763) for supervisor, or its equivalent”
For Class III and Class IV work, the competent person is trained in a manner consistent with EPA requirements for training of local education agency maintenance and custodial staff as set forth at 40 CFR 763.92(a)(2).
“for Class III and Class IV work, who is trained in a manner consistent with EPA requirements for training of local education agency maintenance and custodial staff as set forth at 40 CFR 763.92 (a)(2).”
The building/facility owner is the legal entity, including a lessee, which exercises control over management and record keeping functions relating to a building and/or facility in which activities covered by the standard take place.
“Building/facility owner is the legal entity, including a lessee, which exercises control over management and record keeping functions relating to a building and/or facility in which activities covered by this standard take place.”
An industrial hygienist is a professional qualified by education, training, and experience to anticipate, recognize, evaluate and develop controls for occupational health hazards.
“Industrial hygienist means a professional qualified by education, training, and experience to anticipate, recognize, evaluate and develop controls for occupational health hazards.”
Not covered here
The duties of the competent person and of building/facility owners in later paragraphs of 1926.1101 are not covered in this set. We only write what an official source states, so study these parts with your certifying program's materials.
Exposure limits and exposure terms
The employer shall ensure that no employee is exposed to an airborne concentration of asbestos in excess of 0.1 fiber per cubic centimeter of air as an eight (8) hour time-weighted average (TWA).
“The employer shall ensure that no employee is exposed to an airborne concentration of asbestos in excess of 0.1 fiber per cubic centimeter of air as an eight (8) hour time-weighted average (TWA),”
Under the excursion limit, the employer shall ensure that no employee is exposed to an airborne concentration of asbestos in excess of 1.0 fiber per cubic centimeter of air (1 f/cc) as averaged over a sampling period of thirty (30) minutes.
“The employer shall ensure that no employee is exposed to an airborne concentration of asbestos in excess of 1.0 fiber per cubic centimeter of air (1 f/cc) as averaged over a sampling period of thirty (30) minutes,”
Both limits are determined by the method prescribed in appendix A to the section, or by an equivalent method.
“as determined by the method prescribed in appendix A to this section, or by an equivalent method.”
Employee exposure means the exposure to airborne asbestos that would occur if the employee were not using respiratory protective equipment.
“Employee exposure means that exposure to airborne asbestos that would occur if the employee were not using respiratory protective equipment.”
A fiber is a particulate form of asbestos, 5 micrometers or longer, with a length-to-diameter ratio of at least 3 to 1.
“Fiber means a particulate form of asbestos, 5 micrometers or longer, with a length-to-diameter ratio of at least 3 to 1.”
A negative initial exposure assessment is a demonstration by the employer, which complies with the criteria in paragraph (f)(2)(iii), that employee exposure during an operation is expected to be consistently below the PELs.
“Negative Initial Exposure Assessment means a demonstration by the employer, which complies with the criteria in paragraph (f)(2)(iii) of this section, that employee exposure during an operation is expected to be consistently below the PELs.”
Not covered here
The sampling method in appendix A and the exposure assessment and monitoring requirements (paragraph (f)) are not covered in this set. We only write what an official source states, so study these parts with your certifying program's materials.
Multi-employer worksites
On multi-employer worksites, an employer performing work requiring the establishment of a regulated area shall inform other employers on the site of the nature of its work with asbestos and/or PACM, of the existence of and requirements pertaining to regulated areas, and of the measures taken to ensure that employees of the other employers are not exposed to asbestos.
“On multi-employer worksites, an employer performing work requiring the establishment of a regulated area shall inform other employers on the site of the nature of the employer's work with asbestos and/or PACM, of the existence of and requirements pertaining to regulated areas, and the measures taken to ensure that employees of such other employers are not exposed to asbestos.”
Asbestos hazards at a multi-employer work site shall be abated by the contractor who created or controls the source of asbestos contamination.
“Asbestos hazards at a multi-employer work site shall be abated by the contractor who created or controls the source of asbestos contamination.”
The rule's example: if there is a significant breach of an enclosure containing Class I work, the employer responsible for erecting the enclosure shall repair the breach immediately.
“For example, if there is a significant breach of an enclosure containing Class I work, the employer responsible for erecting the enclosure shall repair the breach immediately.”
In addition, all employers of employees exposed to asbestos hazards shall comply with applicable protective provisions to protect their employees.
“In addition, all employers of employees exposed to asbestos hazards shall comply with applicable protective provisions to protect their employees.”
The rule's example: if employees working immediately adjacent to a Class I job are exposed because of inadequate containment, their employer shall take one of the options: remove the employees from the area until the enclosure breach is repaired, or perform an initial exposure assessment under paragraph (f).
“For example, if employees working immediately adjacent to a Class I asbestos job are exposed to asbestos due to the inadequate containment of such job, their employer shall either remove the employees from the area until the enclosure breach is repaired; or perform an initial exposure assessment pursuant to (f) of this section.”
All employers of employees working adjacent to regulated areas established by another employer on a multi-employer work-site shall take steps on a daily basis to ascertain the integrity of the enclosure and/or the effectiveness of the control method relied on by the primary asbestos contractor to assure that asbestos fibers do not migrate to such adjacent areas.
“All employers of employees working adjacent to regulated areas established by another employer on a multi-employer work-site, shall take steps on a daily basis to ascertain the integrity of the enclosure and/or the effectiveness of the control method relied on by the primary asbestos contractor to assure that asbestos fibers do not migrate to such adjacent areas.”
All general contractors on a construction project which includes work covered by the standard shall be deemed to exercise general supervisory authority over that work, even though the general contractor is not qualified to serve as the asbestos competent person.
“All general contractors on a construction project which includes work covered by this standard shall be deemed to exercise general supervisory authority over the work covered by this standard, even though the general contractor is not qualified to serve as the asbestos “competent person” as defined by paragraph (b) of this section.”
As supervisor of the entire project, the general contractor shall ascertain whether the asbestos contractor is in compliance with the standard, and shall require that contractor to come into compliance when necessary.
“As supervisor of the entire project, the general contractor shall ascertain whether the asbestos contractor is in compliance with this standard, and shall require such contractor to come into compliance with this standard when necessary.”
Sources
- eCFR: 29 CFR 1926.1101, Asbestos (as of Nov 4, 2026)Checked November 6, 2026
Other Asbestos study guides: Regulated areas and exposure monitoring, Methods of compliance, Respirators, protective clothing and hygiene facilities, Communication of hazards, training and housekeeping, Medical surveillance, recordkeeping and the competent person, Schools (AHERA): responsibilities, inspections, sampling and assessment, Schools (AHERA): response actions, O&M, management plans and records