Standard Interpretations - Table of Contents Standard Interpretations - Table of Contents
• Standard Number: 1926.1101(b); 1926.1101(g)

August 26, 2002

Jack Eisenbach, P.E.
Jack Eisenbach Engineering, P.C.
291 Genesee Street
Utica, New York 13501

Dear Mr. Eisenbach:

Thank you for your January 8, 2002 letter to the Occupational Safety and Health Administration’s (OSHA’s) Directorate of Compliance Programs regarding Class IV asbestos work. This letter constitutes OSHA's interpretation only of the requirements discussed and may not be applicable to any question not delineated within your original correspondence. Your questions are summarized below, followed by our responses.

Background: The 1994 construction asbestos standard at 29 CFR 1926.1101 and its preamble describe four classes of decreasingly hazardous types of construction activity that are matched with decreasingly stringent control requirements.
  • Class I asbestos work, the highest risk activity, involves the removal of thermal system insulation (TSI) and surfacing asbestos containing material (ACM) and presumed asbestos containing material (PACM).
  • Class II asbestos work, which is not as risky, includes activities involving the removal of ACM which is not thermal insulation or surfacing material.
  • Class III asbestos work involves repair and maintenance activities that are likely to disturb ACM or PACM.
  • Class IV asbestos work is maintenance and custodial activities where ACM and PACM is contacted but not disturbed and also applies to clean up of waste dust and debris from Class I, II, or III activities.
Disturbance of ACM or PACM is defined in 29 CFR 1926.1101(b) as an activity that disrupts the matrix of, crumbles or pulverizes, or generates visible debris from ACM or PACM. The definition of disturbance includes undefined operations that might result in release of fibers from the material in which they are embedded.

Although Class IV asbestos workers have a lower risk of asbestos exposure than other asbestos workers, and the exposure control requirements for Class IV asbestos workers are more lenient, the employer must still protect the health and safety of these workers.

Question 1: Is over spray on concrete or block walls from the original application of a surfacing material (i.e., fire proofing) debris or intact material?

Reply: Over spray of asbestos containing surfacing material on concrete or block walls is not debris; it is surfacing material that was applied to an accidental surface. Even if it is not intact (i.e., if it is cracking or crumbling), it is still not debris, but is ACM and needs to be handled as such.

Question 2: Does removal of the above material constitute Operations and Maintenance (O&M) or abatement under Class I?

Reply: Removal of ACM or PACM surfacing material from concrete or block walls is Class I asbestos work.

Question 3: If a contractor splatters fireproofing material on a wall surface during abatement (in excess of 160 square feet of area with bits of splatter on it), leaves it there, and it dries on the spot, is the material debris or ACM requiring regular abatement removal?

Reply: A competent person must evaluate the work and classify the operation. Generally, removing ACM or PACM fireproofing material is Class I asbestos work. If the work to be performed is repair or maintenance and involves removing no more ACM or PACM than can be contained in one glove bag or waste bag, this work could be Class III asbestos work. If the material adheres loosely to the wall and can be easily washed off without disturbing the ACM or PACM, it is debris and can be removed from the wall by following the procedures for Class IV asbestos work. Required procedures include wet methods, HEPA vacuums, and prompt clean up of debris containing ACM or PACM.

Question 4: The last question in the Methods of Compliance section of CPL 2-2.63 states that clean up of sizable amounts of asbestos waste and debris are either a Class I, II, or III activity unless the work involves contact with but not disturbance of the asbestos waste or debris. What does sizable mean?

Reply: The OSHA directive to which you referred is CPL 2-2.63 (REVISED), Inspection Procedures for Occupational Exposure to Asbestos Final Rule 29 CFR Parts 1910.1001, 1926.1101, and 1915.1001, which was revised January 9, 1996. For convenience, we have repeated the directive’s question-and-answer below.
Q: What are “asbestos spills/emergency cleanups” under the Construction standard, and how are they classified?

A: Clean up of sizable amounts of asbestos waste and debris is covered by the Construction standard. However, an asbestos spill has occurred when, for example, water damage occurs in a building or facility, and sizable amounts of ACM and/or PACM are dislodged. A competent person shall evaluate the site and ACM/PACM to be handled, and based on the type, condition and extent of the dislodged material, classify the cleanup as Class I, II, or III. Only if the material was intact and the cleanup involved mere contact of ACM, rather than disturbance, could there be a Class IV classification. An example might be the collection and disposal of dislodged intact ceiling tiles. Since collecting the tiles and disposing of them can be accomplished by careful handling, and would not result in disturbance of the material, this activity would be a Class IV job. As such, it would still have to be assessed by a competent person. Wet methods, HEPA vacuuming and prompt disposal are also required.
OSHA expects the competent person to determine the classification of the spill or emergency cleanup. ACM or PACM that exceeds the amount that can be contained within one standard-sized glove bag or waste bag is an example of a “sizable” amount.

Question 5: Is there a limit on the amount of debris from an abatement project done six months before clean up that can be cleaned up as an operations and maintenance project under Class IV? The following scenario describes the situation.

At the end of a major abatement project involving fireproofing, thousands of square feet of ACM debris was left in chases, onwalls, in shafts, on piping and mechanical equipment, and on ceilings. The contractor’s contention is that the material could all be cleaned up as a Class IV operations and maintenance project without using asbestos workers or calling it an abatement. Class IV is the only class of asbestos work where operations and maintenance work is included, but the standard does not clearly define the extent of work covered. The directive, CPL 2-2.63, does not define the extent of work related to debris clean up covered by Class IV.

Reply: Except in roofing operations, the construction standard requires: “prompt clean-up and disposal of wastes and debris contaminated with asbestos in leak-tight containers” for all asbestos work. If the abatement contractor cleaned up ACM wastes and debris promptly, “thousands of square feet of ACM debris” would not be left at the end of the project. It appears that the project you describe did not comply with 29 CFR 1926.1101(g)(1)(iii).

If a facility contains extensive ACM or PACM debris as you describe, a competent person must assess the potential exposures and classify the work. The assessment must cover all expectedtasks during the entire abatement operation, including the clean up. The job would be considered Class IV work only if the material to be cleaned up was intact and cleanup involved mere contact with ACM and not disturbance.

Class IV asbestos work includes maintenance and custodial activities but is not the only class which includes maintenance work. Class III asbestos work also includes repair and maintenance operations, and applies where ACM, including thermal system insulation (TSI) and surfacing ACM and PACM, is likely to be disturbed.

There is no limit on the amount of debris that can be cleaned up as Class IV asbestos work. The Class IV characterization applies to situations where there is an indication that surfaces are contaminated with ACM or PACM. However, the asbestos work cannot be Class IV if the ACM or PACM debris, waste, or dust is “disturbed,” that is, broken into smaller pieces or fibers during the clean-up process.

Question 6: Is the removal of a suspended ceiling that is contaminated with asbestos debris in varying quantities a Class IV or a Class I project? For clarification, the debris in this case is material which either during the initial installation or through erosion and wear during the years fell on top of the ceiling tile and supporting structures.

Reply: If the ceiling tiles do not themselves contain asbestos but are contaminated with asbestos “debris,” then their removal could be Class IV asbestos work but only under the following conditions:
  • A competent person assesses the work.
  • The asbestos debris is removed without disturbing the debris. For example, the ceiling tiles could be HEPA-vacuumed without breaking the debris into smaller pieces or releasing asbestos fibers.
  • Wet methods, HEPA vacuuming, and prompt disposal are required.
As you may know, the OSHA regulations are minimum requirements. As described in the asbestospreamble, the PELs are not entirely protective. A proactive employer will use reasonable engineering controls and work practices to reduce exposures even when the standard does not require them.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA requirements are set by statute, standards and regulations. Our interpretationletters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult the OSHA website at If you have any further questions, please feel free to contact the [Office of Health Enforcement] at (202) 693-2190.


Richard E. Fairfax, Director
[Directorate of Enforcement Programs]

Standard Interpretations - Table of Contents Standard Interpretations - Table of Contents