Occupational Safety and Health Administration (1998)
On January 10, 1997, the Occupational Safety and Health Administration (OSHA) issued a standard that lowered the limit on worker exposures to methylene chloride (MC). This new standard greatly reduces the chance of developing health problems from working in facilities that use MC.
Worker exposures to MC occur mainly through breathing its vapors. MC can also pass through workers' skin if it gets on their body or clothes. Occasionally, workers can swallow small amounts of MC if they don't wash their face and hands before eating, or if they eat in contaminated work areas. Short-term exposure to high levels of MC can cause dizziness, headaches, a lack of coordination, and irritation of the skin, eyes, mucous membranes, and respiratory system. Long-term exposure causes cancer in laboratory animals. Studies in workers suggest an association between MC exposures and certain types of cancer. OSHA considers MC to be a potential occupational carcinogen. Exposure to MC may also make the symptoms of heart disease (e.g., chest pains, angina) worse.
About 9,505 construction companies use products that contain MC. Exposure often happens when workers are stripping paint or other coatings, applying foam, painting with epoxy paint, cleaning equipment with solvents, and spraying adhesives. Workers are more likely to be exposed to high levels of MC when working in small, enclosed spaces that are not well ventilated. The following describes some engineering controls and work practices that you may find helpful in reducing worker exposures to MC at your site.
Employers must monitor worker exposures to MC to determine whether engineering controls or work practices are necessary. Where engineering controls are already in place, employers must monitor worker exposures to determine the effectiveness of the controls and whether or not improvements or additional control methods are needed. Note: Initial monitoring is not necessary if employees are exposed to MC for fewer than 30 days per year, and the employer uses direct-reading instruments giving immediate results and providing sufficient information to determine the necessary control measures to reduce exposures to acceptable levels.
The revised standard published on September 22, 1998 (FR 63; 50712-50732) contains additional STEL monitoring requirements for those specific industries taking advantage of the extended compliance dates. For additional information on monitoring for MC, see OSHA Methylene Chloride Facts No. 01 or OSHA's Chemical Sampling Information which is accessible through OSHA's web site.
If monitoring results indicate that worker exposures to MC are above established limits when working on or near a specific operation, and new or improved controls are necessary, consider using one or more of the following ventilation control options:
After you install a new ventilation system, you must monitor worker exposures again to determine whether the system is effective. Note: Check with the appropriate local, county, or state environmental office to make sure you have the required permits if you will be exhausting MC directly outside.
General (or dilution) ventilation uses fans or open windows to move clean air through the work area. This does not confine MC vapors to one area, so it does not protect workers as well as LEV. General ventilation can sometimes reduce MC to acceptable levels in areas where exposures are not very high.
Keep MC Vapors Contained
Avoid Breathing MC Vapors
Avoid Direct Skin Contact with MC
Minimize the Chance of Spills and Leaks
Take Extra Precautions in Low and Confined Spaces
MC vapors are heavier than air, so they tend to move to low, unventilated spaces.
Take Personal Precautions
Using products that do not contain MC is a good way to reduce worker exposure to MC. Many adhesives, solvents, foams, and paints no longer use MC as a propellant and are widely available (check labels). In addition, a number of paint strippers that do not contain MC are currently available.
Keep in mind that substitutes may also present health and safety hazards to workers. Always select substitutes that reduce hazards, and always refer to the substitute's material safety data sheet to find out about any control measures and protective equipment you must use to protect workers.
If engineering controls and work practices do not reduce MC exposures to an acceptable level, workers must wear supplied-air respirators. Respirators are the least preferred method of controlling employee exposure. Supplied-air respirators must have a clean air supply through the use of compressed air tanks containing air meeting at least the requirements for Grade D breathing air, or a breathing air type compressor with the air intake located in an area with a clean air supply. CAUTION: Filter cartridge respirators cannot be used because MC can pass through available cartridges leaving respirator wearers unprotected.
Employers with 1 to 19 employees (in the selected application group) have until:
Employers with 1 to 19 employees (not in the selected application group) have until:
Employers with 20 to 49 employees (in the selected application group) have until:
Employers with 50 or more employees (in the selected application group) have until:
Employers with 20 or more employees (not in the selected application group) have until:
* Selected application group are those who use MC in construction work for restoration and preservation of buildings, painting and paint removal, cabinet making, or floor refinishing and resurfacing.
For more information concerning consultation assistance, contact the nearest OSHA office (look under state listings for the Department of Labor), refer to the listings on OSHA's web site, or contact OSHA's Office of Information at (202) 219-8151.Back to Top
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