Purpose:	This instruction establishes policies and provides clarification to ensure uniform enforcement of the Occupational Exposure to Methylene Chloride Standard, 29 CFR 1910.1052, 29 CFR 1915.1052, and 29 CFR 1926.1152.
Scope:	OSHA-wide.
References:	Federal Register, Volume 62, Number 7, January 10, 1997, pages 1493-1619: Occupational Exposure to Methylene Chloride, Final Rule; Federal Register, Vol 62, Number 249, December 18, 1997, pages 66275-66277, Methylene Chloride, Partial Stay; OSHA Instruction, CPL 2.103, Field Inspection Reference Manual; OSHA Instruction, CPL 2-2.54, Respiratory Protection Program Manual; Federal Register, Volume 63, Number 5, January 8, 1998, pages 1152-1300, Respiratory Protection: Final Rule; See paragraph III for additional references.
Cancellations:	None
State Impact:	See Paragraph VI
Action Offices:	Regional and Area Offices and State Consultation Programs
Originating Office:	Office of Health Compliance Assistance(OHCA)
Contact:	OHCA, (202-219-8036) N3468, Frances Perkins Building 200 Constitution Avenue, NW Washington, DC 20210

By and Under the Authority of
Charles N. Jeffress
Assistant Secretary

ABSTRACT

1. Purpose.

2. Scope.

3. References.

4. Action Information.

   1. Responsible Office.

   2. Action Offices.

   3. Information Offices.

5. Action.

6. Federal Program Change.

7. Background.

   Figure 1: COMPLIANCE DATES

8. General Considerations.

9. Inspection Guidelines for the Occupational Exposure to Methylene Chloride Standard.

   1. Collecting Information from the Employer.

   2. Inspecting a workplace where the employer has not assessed the methylene chloride exposure.

      4. Remote sampling.

   3. Additional Inspection Guidance.

10. Specific Provisions of 29 CFR 1910.1052.

11. Classification and Grouping of Violations.

12. Authorization to Review Limited Medical Information.

13. Training for OSHA Personnel.

14. Personal Protective Equipment (PPE).

15. Appropriations Language.

Appendix A: QUESTIONS AND ANSWERS

1. Background Information.

2. Regulatory Text Information.

   1. Scope and Application.

   2. Exposure Monitoring.

   3. Regulated Areas.

   4. Methods Of Compliance.

   5. Respiratory Protection.

   6. Medical Surveillance.

   7. Hazard Communication.

   8. Employee Information and Training.

   9. Recordkeeping.

   10. Dates.

Appendix B: METHYLENE CHLORIDE EXPOSURE TRACKING

1. Purpose.

2. Methylene Chloride Air Concentration Measurements.

Appendix C: EVALUATING THE METHYLENE CHLORIDE HAZARDS AND THE EFFECTIVENESS OF THE PROTECTIVE MEASURES USED

1. Air Sampling.

2. Evaluation of Airflow.

3. Evaluation of Spills.

4. Evaluation of Protective Clothing and Equipment.

5. Evaluation of Supplied Air Systems.

1. Purpose. This instruction establishes policies and provides clarification to ensure uniform enforcement of the Occupational Exposure to Methylene Chloride Standard, 29 CFR 1910.1052, 29 CFR 1915.1052, and 29 CFR 1926.1152.

2. Scope. This instruction applies OSHA-wide.

3. References.

   1. Federal Register, Volume 62, Number 7, January 10, 1997, pages 1493-1619: Occupational Exposure to Methylene Chloride, Final Rule.

   2. OSHA Instruction, CPL 2.103, September 26, 1994, Field Inspection Reference Manual.

   3. OSHA Instruction, CPL 2-2.30, November 14, 1980, Authorization of Review of Medical Opinions.

   4. OSHA Instruction, CPL 2-2.32, January 19, 1981, Authorization of Review of Specific Medical Information.

   5. OSHA Instruction, CPL 2-2.33, February 8, 1982, Rules of Agency Practice and Procedure Concerning OSHA Access to Employee Medical Records-Procedures Governing Enforcement Activities.

   6. OSHA Instruction, CPL 2-2.46, January 5, 1989, Authorization and Procedures

   7. OSHA Instruction, CPL 2-2.54, February 10, 1992, Respiratory Protection Program Manual.

   8. MEMORANDUM FOR CONSULTATION PROJECT MANAGERS, REGIONAL ADMINISTRATORS, AND STATE DESIGNEES FROM PAULA O. WHITE, DIRECTOR, Federal-State Operations, January 21, 1998, SUBJECT: Methylene Chloride - Requests for Consultation Assistance.

   9. Federal Register, Volume 62, Number 249, December 18, 1997, pages 66275-66277, Methylene Chloride; Partial Stay.

   10. Federal Register, Volume 63, Number 5, January 8, 1998, pages 1152-1300: Respiratory Protection; Final Rule.

4. Action Information.

   1. Responsible Office. Office of Health Compliance Assistance.

   2. Action Offices. OSHA Regional and Area Offices, State Plan State Offices, and State Consultation Programs.

   3. Information Offices. Consultation Project Offices; manufacturers and users of methylene chloride and methylene chloride products.

5. Action. OSHA Regional Administrators and Area Directors shall use the guidelines in this instruction to ensure uniform enforcement of the Occupational Exposure to Methylene Chloride Standard, 29 CFR 1910.1052, 29 CFR 1915.1052, and 29 CFR 1926.1152

6. Federal Program Change. This instruction describes a Federal Program Change for which State adoption is not required but notice of State intent must be provided. States have sixty days from the date of this instruction to provide to their Regional Administrator a notification of whether the State intends to adopt the procedures outlined in this instruction. The notification should specify whether the State intends to follow the limitations set out in Section XV of this instruction.

   NOTE: In order to effectively enforce a new or revised standard, guidance to compliance staff is necessary. Therefore, although adoption of this instruction is not required, States are expected to have enforcement policies and procedures which are at least as effective as OSHA's.

   As noted in Section XV of this instruction, the House/Senate Conference Report on the Labor/HHS Appropriations Act directs OSHA to limit enforcement of the methylene chloride standard in certain circumstances. While not directly bound by this limitation, States are encouraged to follow a policy similar to that set out in Section XV.A.3 of this instruction.

   In accordance with the Conference Report, OSHA has issued a memorandum requiring all consultation projects operating under section 7(c)(1) of the Act to give certain employers the highest priority for receiving consultation services and not to refer to enforcement those employers unable to comply with this standard due to infeasibility. The eight States which provide private sector consultation services under their State plans are strongly encouraged to follow similar policies to those set out in Sections XV.A.1 and 2 of this instruction.

7. Background.

   1. The final Occupational Exposure to Methylene Chloride Standards, 29 CFR 1910.1052, 29 CFR 1915.1052, and 29 CFR 1926.1152 supersede the current regulations for employee exposure to methylene chloride (MC), also known as dichloromethane (DCM), that are contained in the OSHA air contaminant standards 29 CFR 1910.1000, 29 CFR 1915.1000, and 29 CFR 1926.55, for General Industry, Shipyards, and the Construction Industry, respectively. The final rule establishes permissible exposure limits of 25 ppm (8-hour TWA) and 125 ppm (15-minute STEL). In addition to the PELs, the standard contains provisions typical of those found in OSHA health standards promulgated under section (6)(b)(5) of the Act. Depending on exposure conditions at the workplace, these provisions include requirements for:

      1. Monitoring the exposures of workers,

      2. Establishing regulated areas to reduce the number of workers potentially exposed,

      3. Implementing engineering and work practice controls to achieve the necessary reductions in exposure,

      4. Providing respiratory protection and protective clothing and equipment where necessary,

      5. Making hygiene facilities available where necessary,

      6. Making medical surveillance available,

      7. Communicating information about methylene chloride to workers and training them in its safe use, and

      8. Keeping records related to the standard.

   2. The standard was published in the Federal Register on January 10, 1997, and took effect on April 10, 1997. A partial administrative stay of the standard was granted December 18, 1997. The following table provides the subsequent final dates for complying with the standard:

   

8. General Considerations. The final standards, 29 CFR 1910.1052, 29 CFR 1926.1152, and 29 CFR 1915.1052, apply to all occupational exposures to methylene chloride in general industry, the construction industry, and shipyard employment. Shipyards are entities engaged in shipbuilding, ship repair, or shipbreaking. General Industry Standard, 29 CFR 1910.1052, applies to marine terminal and longshoring employment only insofar as affected employees are exposed to hazards that are not addressed by compliance with parts 1917 and 1918, respectively. OSHA will be finalizing standards for marine terminals and longshoring operations that will set forth the requirements that apply to chemical handling in the cargo handling environment. None of the standards apply to Agriculture Employment covered under 29 CFR 1928.

9. Inspection Guidelines for the Occupational Exposure to Methylene Chloride Standard.

   1. Collecting Information from the Employer. During the opening conference the compliance officer should collect information that will be of assistance in the conduction of the inspection. The compliance officer should request:

      1. That the employers provide required documents, e.g., medical surveillance records, training records, the respiratory protection program for all affected employees, and material safety data sheets (MSDS) for products containing methylene chloride.

      2. That the employers provide a copy of any written program, if available, for improving or instituting engineering and work practice controls for limiting employee exposure to methylene chloride.

      3. That prior to the walk-around, the employer provides copies of employee exposure monitoring data, objective data, and any other employee exposure assessment data that may be available. These data provide the compliance officer with information necessary to develop a strategy for inspecting the workplace and to determine the level of protection needed to safely conduct the inspection.

   2. Inspecting a workplace where the employer has not assessed the methylene chloride exposure.

      1. Some employers will not have established regulated areas nor determined the airborne levels of methylene chloride in their workplace. This situation could create a methylene chloride exposure risk for compliance officers. Before the compliance officer goes out to a worksite where the potential for exposure to methylene chloride exists, the compliance officer shall:

         1. Search the OCIS Lab Report file for previous methylene chloride sample results for the establishment.

         2. Review the OCIS OSHA Air Sampling History to identify methylene chloride air concentration levels for the establishment industry.

      2. The best approach for conducting the inspection will depend on the circumstances and will have to be determined on a case by case basis. Some possible approaches are as follows:

         1. The compliance officers keep close track of their methylene chloride exposures, avoid exposures above the PELs, and wear no respirators. In some cases the compliance officers may have to do remote sampling of employee exposures to methylene chloride in order to avoid overexposures.

         2. The compliance officers keep close track of their methylene chloride exposures and use a self-contained breathing apparatus (SCBA) as required for protection against methylene chloride concentrations above the PELs. The compliance officers must be trained in using and wearing an SCBA. Staff from the Health Response Team may be available to conduct the inspection if there is no compliance officer in the Area Office or elsewhere in the Region with such training.

      3. Upon initiation of the inspection, compliance officers shall:

         1. Screen the methylene chloride air concentration levels and track their exposures with an instantaneous reading direct reading instrument or detector tubes. (Some guidance on selecting a monitoring device is contained in Appendix B.)

         2. Determine what approach to use that will best protect them from methylene chloride concentrations above the PELs or that will enable them to avoid methylene chloride concentrations above the PELs while conducting the inspection and documenting violations. (Note: The use of air-purifying respirators for protection from methylene chloride concentrations above the PELs is not an option, since the Methylene Chloride Standard only permits this type of respirator for escape. However, compliance officers who will not be overexposed to methylene chloride, may wear an air-purifying respirator as an added precaution if they wish to do so.)

         3. Consult with the Area Office and obtain its approval of the approach before proceeding further with the inspection.

      4. Remote sampling.

         1. A compliance officer may use remote sampling to document violations if after considering the prospective problems with remote sampling:

            (1)The compliance officer determines that the problems will not be significant in the case at hand, or

            (2)The compliance officer can resolve the problems in the case at hand.

         2. In a case where the compliance officer never sees the employees at work or the work processes, potential problems with remote sampling include:

            (1)Tampering with the sampling device such as turning the pump off or placing the sampler nearer or farther away from the point that would best indicate an employee's exposure.

            (2)A pump failure or malfunction could occur without the compliance officer immediately noting the event.

            (3)An employee may not return at the appropriate time for changing the sampling media.

            (4)Inability of the compliance officer to fully evaluate the work practices and engineering controls for determining whether the employer has instituted all feasible controls.

         3. If a compliance officer can set the employee up with sampling equipment, and stand far enough away from the process to avoid overexposure, but still close enough to observe the process, remote sampling may not present any significant problems. In such a case the compliance officer would be able to assure the validity of the sample and also observe the work processes for evaluating the work practices and engineering controls. Plus, the compliance officer may be able to occasionally approach the employee for a short period to more closely observe the work process and sampling equipment and still avoid overexposure.

      5. The compliance officers shall keep a running record of the estimated time spent in various air concentrations of methylene chloride for calculating their daily 8-hour TWA and short term exposures. The Area Offices shall keep records of the compliance officers' exposures.

   3. Additional Inspection Guidance. Appendices A and C contain additional information that will assist the compliance officer in evaluating the employer's compliance with the Methylene Chloride Standard.

10. Specific Provisions of 29 CFR 1910.1052. Guidelines and clarifications relating to specific provisions of the standard are provided in Appendix A, Questions and Answers and Appendix C, FACTORS TO CONSIDER IN EVALUATING METHYLENE CHLORIDE CONTROL AND EMPLOYEE EXPOSURE.

11. Classification and Grouping of Violations. The procedures in the Field Inspection Reference Manual, Chapter III, paragraphs C.2. and C.5., should be followed. If deviations appear appropriate, they must be discussed and coordinated with the Regional Office.

12. Authorization to Review Limited Medical Information. Appropriately qualified compliance personnel, under the direction of the Team Leader, are authorized to review medical records and medical opinions pertinent to a review of compliance with the methylene chloride standard. This authorization has limitations and procedures set forth in OSHA Instructions CPL 2-2.30, CPL 2-2.32, CPL 2-2.33, and CPL 2-2.46 which must be followed.

13. Training for OSHA Personnel. Only experienced and trained compliance officers shall lead methylene chloride inspections. Compliance officers are expected to know the following:

    1. The potential hazards which may be encountered at the site, including the potential hazards of methylene chloride.

    2. The contents of the Methylene Chloride standard including the appendices.

    3. The contents of this instruction.

    4. The appropriate protective equipment to be worn. Each compliance officer who uses protective equipment shall be trained in the proper care, use, and limitations of the equipment. Use of respiratory protection by compliance officers is covered in OSHA Instruction CPL 2-2.54.

    5. The appropriate emergency procedures.

14. Personal Protective Equipment (PPE). Regional Administrators and Area Directors shall ensure that appropriate PPE is available for the compliance officers and used when required.

    1. Air-purifying respirators may be used only where methylene chloride exposure does not exceed either PEL.

    2. For inspections in which the compliance officer could experience skin or eye exposure to liquid methylene chloride, protective clothing and eye protection that is resistant to methylene chloride shall be worn.

15. Appropriations Language.

    1. The 1998 FY appropriations bill (H.R. 2264) for the Departments of Labor, Health and Human Services, and Education does not address methylene chloride. The House/Senate Conference Report does, however, and OSHA is expected to comply with its direction. In the Report, OSHA is directed to issue the following compliance directive to its field compliance officers. Compliance Officers are not to enforce the Methylene Chloride Standard unless:

       1. The agency makes available to employers with fewer than 150 employees in the furniture stripping and foam manufacture or fabricating industries an on-site consultation program that will give the establishments in these industries highest priority for receiving consultative services;

       2. Any establishment that receives a consultation visit and is found to be out of compliance with the requirements of the standard due to infeasibility will receive additional compliance assistance but will not be referred for inspection; and

       3. Establishments in these industries that receive an OSHA enforcement inspection and are found to be out of compliance with the exposure limit requirements of the Methylene Chloride Standard because compliance is economically or technologically infeasible will not be cited for a violation of that requirement, but instead OSHA will work with the employer to seek and employ alternative means of abatement.

    2. The Directorate of Federal-State Operations implemented item 1. above by a memorandum dated January 21, 1998, provided to the Consultation Project Managers, Regional Administrators, and State Designees. The memorandum advises all 7(c)(1) Consultation Project Managers, whether in State Plan or Federal enforcement States, to give employers in the furniture stripping, foam manufacture, or foam fabricating industries, who have fewer than 150 employees, highest priority for receiving consultation services. The effective date for this change in priority status for consultation services is February 2, 1998.

    3. OSHA Regional and Area Offices shall implement item 2. above by refusing any referral from a Consultation Office that is made because the employer is found to be out of compliance with the requirements of the methylene chloride standard due to infeasibility. (See Section VI for State Plan enforcement implications.)

    4. OSHA Regional and Area Offices shall implement item 3. above by not citing the employer for violating the PELs if it is economically or technologically infeasible for the employer to achieve them with a combination of engineering and work practice controls. The OSHA Area Offices shall document that the PELs are exceeded, however, and shall enforce compliance with the other provisions of the standard. (See Section VI for State Plan enforcement implications.)

1. Background Information.

   Q. What are the adverse health effects associated with exposure to methylene chloride?

   A. These effects include cancer, effects on the heart and central nervous system, and skin or eye irritation.

   Q. Why does the standard contain a short-term exposure limit (STEL) of 125 ppm, measured over a 15-minute period?

   A. The STEL protects employees from the acute toxicity of methylene chloride, the carcinogenic metabolites of methylene chloride, and complements the protection from methylene chloride's carcinogenic effects provided by compliance with the 8-hour time-weighted average (TWA) exposure limit of 25 ppm.

   Q. How does the STEL protect employees from the carcinogenic metabolites of methylene chloride?

   A. Metabolic evidence suggests that the mixed function oxidase system (MFO) pathway (the metabolic pathway not believed to be a major contributor to carcinogenesis) begins to be saturated at approximately 100 ppm and metabolism by the glutathione-S-transferase (GST) pathway (the putative carcinogenic pathway) becomes more important quantitatively at that level. Compliance with the STEL limits metabolism by the GST pathway and protects the employee from excessive exposure to potentially carcinogenic metabolites of methylene chloride.

   Q. What are the acute toxic effects of methylene chloride?

   A. Acute toxicity of methylene chloride is characterized by central nervous system (CNS) effects, such as decreased alertness and coordination, headaches and dizziness, which may ultimately lead to accidents and further exposure to methylene chloride. Methylene chloride also increases carboxyhemoglobin levels. Carboxyhemoglobin can interfere with the oxygen carrying capacity of blood and is a particular problem for individuals who smoke, those who have limited oxygen carrying capacity, those with silent or symptomatic heart disease, and pregnant women. The eyes and skin are irritated by contact with liquid methylene chloride.

   Q. How does exposure to methylene chloride occur?

   A. Employee exposure can occur through inhalation or through skin absorption.

   Q. What are common uses for methylene chloride?

   A. It is frequently used as a process solvent, as a degreasing agent, as a cleaning solvent, as a component of paint strippers, in propellant mixtures in containers for spraying aerosols such as adhesives, and as an auxiliary blowing agent in Polyurethane foam manufacturing.

   Q. What types of work operations are sources of overexposure to methylene chloride?

   A. Many different kinds of work operations, such as methylene chloride manufacturing, furniture paint stripping, metal cleaning, foam blowing, and pharmaceutical manufacturing may overexpose employees to methylene chloride.

2. Regulatory Text Information.

   1. Scope and Application.

      Q. How is the extent of coverage of an employer by the standard determined?

      A. The extent of coverage depends on the level of employee exposure to methylene chloride. The highest level of coverage occurs when employees are exposed above both the 8-hour time-weighted average permissible exposure limit (PEL) and the short term exposure limit (STEL) and could contact liquid methylene chloride. In that case all the requirements of the standard apply. The lowest level of coverage occurs when employees are exposed below both the action level (AL) and the STEL and are not subject to skin contact with liquid methylene chloride. In that case, employers are only required to document that exposures are this low and to provide employee information and training.

      Q. What workplaces are covered by the standard?

      A. The standard applies to all workplaces covered by OSHA in general industry, construction and shipyards, where methylene chloride is produced, released, stored, handled, used, or transported. It applies to workplaces in the marine terminal and longshoring industries only where the industry-specific standards do not address hazards to which employees are exposed. The standard does not apply to the agriculture industry. (See page 1572 of the Federal Register.)

   2. Exposure Monitoring.

      Q. Which employers in the covered industry sectors must make an initial determination of their employees' exposures to methylene chloride?

      A. All employers in the covered industry sectors with workplaces where methylene chloride is known to be present must make an initial determination of employee exposure.

      Q. When is exposure monitoring not required in order to make initial determinations of employee exposure to methylene chloride?

      A. Initial exposure monitoring is not required where:

      • The employer has objective data which demonstrate that employees cannot be exposed at or above the action level or the STEL for methylene chloride.

      • The employer has performed exposure monitoring which meets the requirements of this section within the year prior to the effective date of the final rule. The monitoring must have been of workplace conditions that are similar to conditions existing at the time the rule becomes effective.

      Q. When is it not necessary to monitor employee exposure to methylene chloride with the accuracy specified in the standard?

      A. The accuracy of monitoring requirement of the standard does not apply when the workplace or work operation is transient and employees are exposed on fewer than 30 days a year. In this situation, employers are permitted to use direct reading instruments, such as detector tubes, to estimate exposure and determine what protective measures to provide. While these simple measurement tools often do not meet the accuracy requirements that other types of monitoring methods do, they have the advantage of immediate results and no delay in the provision of protection. Since some short-term jobs, for example, construction projects, may not last long enough for analytical results to be returned from conventional monitoring methods, these direct reading instruments provide an effective compromise that will nevertheless ensure protection for employees in these types of operations.

      Q. What conditions must objective data satisfy in order to exempt an employer from the requirement to perform initial monitoring of employee exposure to methylene chloride?

      A. The objective data must establish the highest methylene chloride exposures likely to occur under reasonably foreseeable conditions of processing, use, or handling in the workplace. The employer must document the data and the analysis of the data that leads to the conclusion that employees cannot be exposed at or above the action level or the STEL for methylene chloride.

      Q. What would be an example of when objective data might be used to provide an exemption from the initial employee exposure monitoring requirement?

      A. It is likely, in a number of products made from, containing or treated with methylene chloride, that an insignificant amount of methylene chloride will be present and that there will be minimal exposure to it. Where this is the case, the exemption provides fabricators or users of the products a means to avoid the burdens of compliance with the standard. The determination that airborne concentrations of methylene chloride will not exceed the action level or the STEL need not be based on data generated by the employer but may, for example, be based upon information provided by the manufacturer of the product being used by the employer.

      Q. What are the minimum conditions when a personal breathing zone air sample taken for one employee can be considered representative of another employee's 8-hour time-weighted average (TWA) exposure to methylene chloride?

      A. A personal breathing zone air sample may be considered to be representative of another employee's 8-hour time-weighted average (TWA) exposure when the employer has taken one or more personal breathing zone air samples covering the duration of exposure for at least one employee who is expected to have the highest methylene chloride exposures in the same job classification in the same work area during every work shift. As long as the employees in the same job classification have similar exposures, the employer may use the result from the employee who was selected for exposure sampling to represent the exposure of the group of employees.

      Q. May an employer also use one or more employees to represent the maximum 15-minute exposure to methylene chloride of all of the employees in each job classification in a work area during every work shift?

      A. Yes. The personal breathing zone air samples taken must indicate the highest likely 15-minute exposures that would occur to employees in that job classification during the work shift.

      Q. May an employer use representative monitoring to comply with a requirement to perform initial monitoring of employee exposures to methylene chloride?

      A. Yes, although the best way to characterize employee exposure is to measure each employee's exposure individually.

      Q. In accordance with 29 CFR 1910.1052(4)(i), the employer shall perform exposure monitoring when a change in workplace conditions indicates that employee exposure may have increased. Is this additional monitoring required after every change in production, process, etc.?

      A. Additional monitoring is not required after those changes in production, process, etc., for which the employer has another sound basis for concluding that the changes have not resulted in a significant increase in employee exposures.

      Q. What is a significant increase in employee exposures?

      A. OSHA interprets a significant increase in employee exposures to be:

      • An instance where at least one previously unexposed employee is exposed at or above the action level for methylene chloride,

      • An instance where at least one employee's exposure increases from below the action level to at or above the action level,

      • An instance where at least one employee's exposure increases from below one or both of the PELs to above one or both of the PELs, or

      • An instance where an employee exposed at or above the action level or above the STEL incurs a 50 percent or greater increase in exposure.

      Q. According to 29 CFR 1910.1052(d)(6)(i), the employer shall provide affected employees or their designated representatives an opportunity to observe any monitoring of employee exposure to methylene chloride conducted in accordance with the standard. May employers choose who will be provided the opportunity to observe the monitoring?

      A. No. The affected employees choose who will observe the monitoring.

   3. Regulated Areas.

      Q. Must every employee entering the regulated area wear a respirator?

      A. Where a reliable estimate of the air concentration of methylene chloride and the time to be spent by the employee in the regulated area shows that there is no potential for overexposure, the employee is not required to wear a respirator while in the regulated area.

      Q. Must the regulated area consist of a fixed location or locations within the plant?

      A. No, the extent of a regulated area may vary depending on the work activity involved. For example, an area in which employee methylene chloride exposures are not normally over the 8 hour TWA or STEL because the methylene chloride is contained inside sealed equipment may need to be designated a regulated area during the time that maintenance work that requires the equipment to be opened takes place.

      Q. Must an employee who is exposed over the 8 hour TWA limit wear a respirator at all times while in the regulated area?

      A. Yes. However, as explained in the preceding answer, the extent of the regulated area may vary during the work shift. If an employee's work station is only within a regulated area during a portion of the work shift, the employee must only use a respirator during that period.

      Q. If the location or boundaries of the regulated area changes during the work day, how must the regulated area be demarcated?

      A. The employer must demarcate the regulated area in any manner that adequately establishes and alerts employees to the boundaries. Movable signs, temporary barriers, or a system of warning lights are among the methods employers could use to demarcate a regulated area that changes in size during the work day.

      Q. What factors must employers consider in determining how to demarcate regulated areas?

      A. Employers are to consider such factors as the configuration of the area, whether the regulated area is permanent, the airborne methylene chloride concentration, the number of employees in adjacent areas, and the period of time the area is expected to have exposure levels above either PEL.

      Q. What employee activities must the employer prohibit in regulated areas?

      A. The employer shall ensure that within a regulated area employees do not engage in nonwork activities which may increase dermal or oral exposure to methylene chloride. For example, the employer shall ensure that employees do not eat, drink, smoke, chew tobacco or gum, or apply cosmetics in the regulated area.

   4. Methods Of Compliance.

      Q. Does the methylene chloride standard require written compliance plans?

      A. No. In 1991 OSHA proposed a requirement that employers establish and implement a written compliance plan which would describe how employee overexposures to airborne methylene chloride would be reduced or brought below the PELs. However, the Agency removed this provision from the final rule in order to reduce employer paperwork. Regardless of size, employers are not required to produce written compliance plans. NOTE: According to 29 CFR 1910.1052(d)(5), within 15 working days after an employer receives monitoring results, they must notify the employee in writing of these results, and if the results indicate an overexposure, the employer shall describe in the written notification the corrective action being taken to reduce employee exposure to or below the 8-hour TWA PEL or STEL and the schedule for completion of this action.

   5. Respiratory Protection.

      Q. When does the standard require employers to use supplied-air respirators to protect employees overexposed or subject to overexposure to methylene chloride?

      A. The standard requires that for all circumstances except during emergency escape, the employer must use supplied-air respirators to protect employees overexposed or subject to overexposure to methylene chloride.

      Q. Why does the standard require employers to use supplied air respirators?

      A. The standard requires supplied air respirators because methylene chloride breaks through the chemical cartridges and canisters used on air purifying respirators in too short a time for these respirators to provide reliable protection. Moreover, methylene chloride provides inadequate warning of when it breaks through chemical cartridges and canisters because the odor threshold concentration level is higher than the PEL values.

      Q. May employers use the controlled negative pressure (CNP) method or the ambient aerosol method for quantitative fit testing of respirators?

      A. These instruments are permitted for quantitative fit testing. Protocols for their use are contained in Appendix A of the revised respiratory protection standard (29 CFR 1910.34) that was published in the Federal Register on January 8, 1998.

   6. Medical Surveillance.

      Q. What action must employers take to comply with 29 CFR 1910.1052(j)(1)(iii), which requires employers to make medical surveillance available to employees who may be exposed to methylene chloride during an emergency?

      A. Employers who have identified operations where a potential for an emergency involving methylene chloride exists must take the necessary action to ensure that, in the event an emergency occurs, facilities will be available and medical assistance will be rendered to exposure victims promptly by physicians or other licensed health care professionals knowledgeable about the toxic effects of methylene chloride.

   7. Hazard Communication.

      Q. Does the Methylene Chloride Standard contain requirements for labeling and for preparing material safety data sheets (MSDS)?

      A. Employers who have already met their longstanding requirements to comply with the Hazard Communication Standard (29 CFR 1910.1200) will have no additional duties with regard to labels and MSDS under the Methylene Chloride Standard. The Methylene Chloride Standard simply indicates what specific hazard information must be provided on labels and material safety data sheets.

   8. Employee Information and Training.

      Q. How does the employer determine when employee information and training must be updated?

      A. The standard does not provide a specific time period for updating the training and information. Instead, it requires that information and training be updated as necessary to ensure that each employee exposed above the action level or the STEL maintains a good understanding of the principles of safe use and handling of methylene chloride in the workplace. Employers can assess whether this understanding is generally present in exposed employees in various ways, such as by observing their actions in the workplace. For example, a pattern of not using appropriate protective equipment or following safe work practices may be an indication that additional information and training is required. This is a performance-oriented requirement that allows each employer to determine how much additional training and information to provide and how often to provide it. The employer must also update the training as necessary whenever there are workplace changes, such as modifications of tasks or procedures or the institution of new tasks or procedures, which increase employee exposure, and where those exposures exceed or can reasonably be expected to exceed the action level.

   9. Recordkeeping.

      Q. Does the methylene chloride standard permit electronic retention and transmission of records?

      A. Electronic retention and transmission of records is acceptable provided the confidentiality of medical records is retained and there is compliance with all relevant provisions of the standard.

      Q. How does the required exposure monitoring record for employers with fewer than 20 employees differ from the required exposure monitoring record for employers with 20 or more employees?

      A. Employers with fewer than 20 employees may provide and maintain less information. These employers may exclude the following information from the record:

      • The operation involving exposure to methylene chloride which is being monitored;

      • Sampling and analytical methods used and evidence of their accuracy; and

      • Type of personal protective equipment, such as respiratory protective devices, worn, if any.

        In OSHA's view, an employer with fewer than 20 employees is very likely to know intimately the operations of the business, including information about exposure monitoring and the use of personal protective equipment. Therefore, the information can be excluded from the employee's records without compromising employee safety and health.

      Q. Are laboratory test results obtained for the purpose of medical surveillance of employees exposed to methylene chloride included in the written medical opinion provided to the employer?

      A. The written medical opinion provided the employer must not include any laboratory test results.

      Q. Must the employer ensure the preservation, retention, and accessibility of laboratory test results obtained for the purpose of medical surveillance of employees exposed to methylene chloride?

      A. The Methylene Chloride Standard does not list laboratory test results among the items that must be included in the medical surveillance record. However, the laboratory test results are employee medical records that must be retained, preserved, and made accessible in accordance with 29 CFR 1910.1020, Access to employee exposure and medical records.

   10. Dates.

       Q. Are companies engaged solely in the fabrication of flexible foam products who use adhesives containing methylene chloride and have 20-99 employees considered to be "Polyurethane foam manufacturers" that are eligible for the extended compliance deadlines for Polyurethane foam manufacturers with 20-99 employees?

       A. No. The extended compliance dates for Polyurethane foam manufacturers with 20-99 employees apply only to those manufacturers who use methylene chloride in blowing the foam. If the only use of methylene chloride is in an adhesive, the extended compliance dates do not apply.

       Q. Is a fabrication operation that uses an adhesive containing methylene chloride and is located within a Polyurethane foam manufacturing facility subject to a different compliance schedule than the foam manufacturing (foam blowing) operation?

       A. No. If a Polyurethane foam manufacturer has 20-99 employees and uses methylene chloride to blow foam, then the compliance schedule for Polyurethane foam manufacturers with 20-99 employees applies for all the operations in the facility involving methylene chloride exposure.

       Q. What methylene chloride exposure limits apply during the period before the start-up dates for the new Methylene Chloride Standard, 29 CFR 1910.1052? (Note that Table Z-2 in 29 CFR 1910.1000 is being amended by deleting the methylene chloride entry. Note also that the start-up date for the new methylene chloride permissible exposure limits for employers with less than 20 employees is not until April 10, 1998.)

       A. As stated at 29 CFR 1910.1052(n)(3) in the Methylene Chloride Standard, the exposure limits in place in 1996 in Table Z-2 will apply to all industries in the interim until the start-up dates are in effect. This means that in the interim period all industries will have to comply with an 8-hour TWA PEL of 500 ppm, an acceptable ceiling concentration of 1000 ppm, and an acceptable maximum peak above the acceptable ceiling concentration for an 8-hour work shift of 2000 ppm for a period not to exceed 5 minutes in any 2 hours. OSHA encourages employers to comply with the new standard as soon as possible in order to protect the health of their workers.

1. Purpose. The information provided in this appendix is intended to aid OSHA compliance officers with determining the method to use to track their methylene chloride exposures during an inspection of a work place.

2. Methylene Chloride Air Concentration Measurements.

   1. Methylene chloride air concentrations can be measured with an approved detector tube or with other direct reading instruments. The sensitivity of detector tubes for methylene chloride is limited. At levels at or below 25 ppm methylene chloride and low humidity, preliminary estimates indicate that it will take approximately 12-14 minutes to obtain a visible color change on the detector tube using the maximum number of pump strokes.

   2. For instantaneous measurement of methylene chloride in air, a photo ionization detector (PID) can be used if is equipped with a high energy lamp (11.4 eV or higher). Calibration of the PID must be done according to the manufacturer's recommendations using isobutylene as a span gas. Because the photo ionization response is not specific for methylene chloride, other chemicals in the work environment will cause a positive interference, and therefore the ppm readings obtained by this device will overestimate the true exposure to methylene chloride.

   3. When a PID is used to monitor the methylene chloride air concentration in a work environment, such as furniture stripping, where a multiple of solvent vapors may exist, it is advisable to measure the methylene chloride air concentration with a detector tube for determining the approximate proportion of the PID response that can be attributed to methylene chloride. For example if the PID reading registers 200 ppm in a work area in which a detector tube reads 75 ppm, then the methylene chloride concentration in air can be estimated to be 40% of the PID reading (75/200X100 ~40%). Because the response signal for methylene chloride will be affected by changes in the composition of the vapors in the work area, it is advisable to periodically verify the response ratio of the PID detector to the detector tube reading.

1. Air Sampling.

   1. If the air concentrations of methylene chloride measured in the work area with detector tubes or other direct reading instruments are below the 12.5 ppm action level, then professional judgement should be exercised in determining what additional sampling to perform. Because concentrations of methylene chloride in air can vary dramatically, and because direct monitoring and detector tube sensitivities have limited accuracy at low levels, in some cases the compliance officer will find it appropriate to conduct personal sampling of the workers to establish if the action level has been exceeded.

   2. Two types of sampling tubes are available for personal sampling. For STEL sampling, a Carbosieve S-III synthetic charcoal sampling tube, (OSHA method #80) may be used. For 8-hour TWA sampling, this sample tube must be changed hourly based upon the recommended flow rate of 0.05 L/min, or a two hour sample can be obtained with this sample tube using a 0.025 L/min sampling rate.

   3. An alternative sampling tube for both STEL and for 8-hour TWA monitoring is the large three-section sample tube containing conventional coconut shell charcoal (OSHA method #59). This sample tube can be used to sample for 3.3 hours at 0.05 L/min, however the sample tube can be used at a lower flow rate (0.025 L/min) to provide a 6.6 hour sampling time. At this reduced sampling rate, a sampling tube can be changed at the lunch break shift, and thus, two sample tubes can be used to monitor each worker over an eight-hour work day.

   4. Area air sampling may be required to establish whether the boundary of the regulated area complies with 29 CFR 1910.1052(e). The large OSHA #59 sample tubes calibrated at 0.025 L/min can be used to obtain an area sample in a location suspected of exceeding either the 25 ppm TWA or the 125 ppm STEL. Alternatively, OSHA method #80 tube can be used for sampling an area for STEL monitoring, or for a short term PEL sample. Detector tube or PID direct reading measurements in an area may be useful in determining the location for conducting area monitoring.

   5. Gas bag samples can also be collected as a means of obtaining air samples. These samples can then be "analyzed" on site using a detector tube or a PID to determine if the air concentration is in excess of the 8-hour TWA PEL or the STEL. This method may be most appropriate in a situation where direct reading PIDs are not available to frequently monitor the methylene chloride concentration in the area over time, and the compliance officer wants to obtain a better picture of the exposure over time than is available from a single detector tube "grab sample" of the air.

2. Evaluation of Airflow.

   1. Smoke tubes can be used to examine the performance of local exhaust ventilation controls by observing the ability of the local exhaust system to capture discharged smoke.

   2. Smoke tubes can be used to determine whether air flows from methylene chloride work areas or regulated areas to nonregulated areas.

3. Evaluation of Spills.

   1. Whereas (f)(3)(ii) requires that incidental spills be promptly cleaned by employees who use the appropriate personal protective equipment and are trained in proper methods of cleanup, caution should be exercised in determining the size of a spill which can be classified as incidental. Methylene chloride is a very volatile solvent and has a high vapor pressure (440 mm Hg at 25 C). Thus a large, pool of methylene chloride spilled on the floor in an enclosed room with no ventilation could produce an air concentration in excess of 500,000 ppm. At this extremely high concentration, an oxygen deficient environment would exist, which in addition to producing a narcotic effect, would cause a rapid loss of consciousness and death.

   2. Another useful example to illustrate the potential hazards created by methylene chloride spills could involve a scenario in which a worker spills a quart of methylene chloride in an enclosed room with dimensions of 15' length by 15' width by 10' ceiling. Because methylene chloride evaporates rapidly (70% as fast as ethyl ether), it can be expected that the entire volume will be rapidly dispersed into the air in the room resulting in an air concentration over 5700 ppm, which exceeds the 2,300 ppm IDLH level reported in the NIOSH 1994 pocket guide. (1990 NIOSH Pocket Guides lists IDLH of 5,000 ppm). Under this scenario, the spill would not be classified as an incidental spill under OSHA's interpretation of 1910.120, and consequently evacuation would be the only appropriate response. Efforts to mitigate the consequences of this spill would require that the employer implement an emergency response as described in 1910.120.

   3. Direct reading PID air monitors can be useful in determining sources of leaks and spills.

4. Evaluation of Protective Clothing and Equipment. NIOSH studies indicate that skin absorption can be a significant route of exposure. It appears that dermal exposure to methylene chloride can occur without producing irritation. Color indicating patches are available from the Salt Lake Technical Center for evaluating the effectiveness of PPE against methylene chloride. Contact the Center for recommendations on how to use these patches.

5. Evaluation of Supplied Air Systems.

   1. The breathing air for supplied air systems must meet the air quality requirements of Grade D or better as specified in CGA specification G-7.1-1989.

   2. Compressed air supplied by oil lubricated compressors must be monitored frequently for carbon monoxide if the compressors are not equipped with continuous carbon monoxide monitors.

   3. Entry of contaminants into the supplied air system must be prevented by locating the compressor air intake in an uncontaminated area or by in-line purification. Proper location will probably be the only practical means of preventing contamination of the breathing air with methylene chloride because of the inability to effectively filter it from air.

   4. Air line couplings must be incompatible with outlets of other gas services.

   5. NIOSH approved respirators must be used. This approval process also applies to the air line hose and the length of hose. See 42 CFR Part 84.

   6. NIOSH approved respirators must only be repaired with approved replacement parts.