California Code of Regulations › Title 8 - Industrial Relations › Division 1 - Department of Industrial Relations › Chapter 4 - Division of Industrial Safety › Subchapter 7 - General Industry Safety Orders › Group 16 - Control of Hazardous Substances › Article 110 - Regulated Carcinogens › Appendix A to Section 5202 - Substance Safety Data Sheet and Technical Guidelines for Methylene Chloride

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
I. Substance Identification
A. Substance: Methylene chloride
						  (CH2Cl2).
B. Synonyms: MC, Dichloromethane (DCM); Methylene
						  dichloride; Methylene bichloride; Methane dichloride; CAS: 75-09-2;
						  NCI-C50102.
C. Physical data:
1. Molecular weight: 84.9.
2. Boiling point (760 mm Hg): 39.8 deg.C (104
						  deg.F).
3. Specific gravity (water=1): 1.3.
4. Vapor density (air=1 at boiling point): 2.9.
5. Vapor pressure at 20 deg.C (68 deg.F): 350 mm
						  Hg.
6. Solubility in water, g/100 g water at 20 deg. C (68
						  deg. F)=1.32.
7. Appearance and odor: colorless liquid with a
						  chloroform-like odor.
D. Uses: MC is used as a solvent, especially where high
						  volatility is required.
It is a good solvent for oils, fats, waxes, resins,
						  bitumen, rubber and cellulose acetate and is a useful paint stripper and
						  degreaser. It is used in paint removers, in propellant mixtures for aerosol
						  containers, as a solvent for plastics, as a degreasing agent, as an extracting
						  agent in the pharmaceutical industry and as a blowing agent in polyurethane
						  foams. Its solvent property is sometimes increased by mixing with methanol,
						  petroleum naphtha or tetrachloroethylene.
E. Appearance and odor:
MC is a clear colorless liquid with a chloroform-like
						  odor. It is slightly soluble in water and completely miscible with most organic
						  solvents.
F. Permissible exposure:
Exposure may not exceed 25 parts MC per million parts
						  of air (25 ppm) as an eight-hour time-weighted average (8-hour TWA PEL) or 125
						  parts of MC per million parts of air (125 ppm) averaged over a 15-minute period
						  (STEL).II. Health Hazard Data
A. MC can affect the body if it is inhaled or if the
						  liquid comes in contact with the eyes or skin. It can also affect the body if
						  it is swallowed.
B. Effects of overexposure:
1. Short-term Exposure:
MC is an anesthetic. Inhaling the vapor may cause
						  mental confusion, light-headedness, nausea, vomiting, and headache. Continued
						  exposure may cause increased light-headedness, staggering, unconsciousness, and
						  even death. High vapor concentrations may also cause irritation of the eyes and
						  respiratory tract. Exposure to MC may make the symptoms of angina (chest pains)
						  worse. Skin exposure to liquid MC may cause irritation. If liquid MC remains on
						  the skin, it may cause skin burns. Splashes of the liquid into the eyes may
						  cause irritation.
2. Long-term (chronic) exposure:
The best evidence that MC causes cancer is from
						  laboratory studies in which rats, mice and hamsters inhaled MC 6 hours per day,
						  5 days per week for 2 years. MC exposure produced lung and liver tumors in mice
						  and mammary tumors in rats. No carcinogenic effects of MC were found in
						  hamsters. There are also some human epidemiological studies which show an
						  association between occupational exposure to MC and increases in biliary (bile
						  duct) cancer and a type of brain cancer. Other epidemiological studies have not
						  observed a relationship between MC exposure and cancer. OSHA interprets these
						  results to mean that there is suggestive (but not absolute) evidence that MC is
						  a human carcinogen.
C. Reporting signs and symptoms:
You should inform your employer if you develop any
						  signs or symptoms and suspect that they are caused by exposure to MC.
D. Warning Properties:
1. Odor Threshold:
Different authors have reported varying odor thresholds
						  for MC. Kirk-Othmer and Sax both reported 25 to 50 ppm; Summer and May both
						  reported 150 ppm; Spector reports 320 ppm. Patty, however, states that since
						  one can become adapted to the odor, MC should not be considered to have
						  adequate warning properties.
2. Eye Irritation Level:
Kirk-Othmer reports that "MC vapor is seriously
						  damaging to the eyes." Sax agrees with Kirk-Othmer's statement. The ACGIH
						  Documentation of TLVs states that irritation of the eyes has been observed in
						  workers exposed to concentrations up to 5000 ppm.
3. Evaluation of Warning Properties:
Since a wide range of MC odor thresholds are reported
						  (25-320 ppm), and human adaptation to the odor occurs, MC is considered to be a
						  material with poor warning properties.III. Emergency First Aid
						  Procedures
In the event of emergency, institute first aid
						  procedures and send for first aid or medical assistance.
A. Eye and Skin Exposures:
If there is a potential for liquid MC to come in
						  contact with eye or skin, face shields and skin protective equipment must be
						  provided and used. If liquid MC comes in contact with the eye, get medical
						  attention. Contact lenses should not be worn when working with this
						  chemical.
B. Breathing:
If a person breathes in large amounts of MC, move the
						  exposed person to fresh air at once. If breathing has stopped, perform
						  cardiopulmonary resuscitation. Keep the affected person warm and at rest. Get
						  medical attention as soon as possible.
C. Rescue:
Move the affected person from the hazardous exposure
						  immediately. If the exposed person has been overcome, notify someone else and
						  put into effect the established emergency rescue procedures. Understand the
						  facility's emergency rescue procedures and know the locations of rescue
						  equipment before the need arises. Do not become a casualty yourself.IV.
						  Respirators, Protective Clothing, and Eye Protection
A. Respirators:
Good industrial hygiene practices recommend that
						  engineering controls be used to reduce environmental concentrations to the
						  permissible exposure level. However, there are some exceptions where
						  respirators may be used to control exposure. Respirators may be used when
						  engineering and work practice controls are not feasible, when such controls are
						  in the process of being installed, or when these controls fail and need to be
						  supplemented. Respirators may also be used for operations which require entry
						  into tanks or closed vessels, and in emergency situations. If the use of
						  respirators is necessary, the only respirators permitted are those that have
						  been approved by the Mine Safety and Health Administration (MSHA) or the
						  National Institute for Occupational Safety and Health (NIOSH). Supplied-air
						  respirators are required because air- purifying respirators do not provide
						  adequate respiratory protection against MC. In addition to respirator
						  selection, a complete written respiratory protection program should be
						  instituted which includes regular training, maintenance, inspection, cleaning,
						  and evaluation. If you can smell MC while wearing a respirator, proceed
						  immediately to fresh air. If you experience difficulty in breathing while
						  wearing a respirator, tell your employer.
B. Protective Clothing:
Employees must be provided with and required to use
						  impervious clothing, gloves, face shields (eight-inch minimum), and other
						  appropriate protective clothing necessary to prevent repeated or prolonged skin
						  contact with liquid MC or contact with vessels containing liquid MC. Any
						  clothing which becomes wet with liquid MC should be removed immediately and not
						  reworn until the employer has ensured that the protective clothing is fit for
						  reuse. Contaminated protective clothing should be placed in a regulated area
						  designated by the employer for removal of MC before the clothing is laundered
						  or disposed of. Clothing and equipment should remain in the regulated area
						  until all of the MC contamination has evaporated; clothing and equipment should
						  then be laundered or disposed of as appropriate.
C. Eye Protection:
Employees should be provided with and required to use
						  splash-proof safety goggles where liquid MC may contact the eyes.V.
						  Housekeeping and Hygiene Facilities
For purposes of complying with the sanitation
						  requirements of Article 9, the following items should be emphasized:
A. The workplace should be kept clean, orderly, and in
						  a sanitary condition. The employer should institute a leak and spill detection
						  program for operations involving liquid MC in order to detect sources of
						  fugitive MC emissions.
B. Emergency drench showers and eyewash facilities are
						  recommended. These should be maintained in a sanitary condition. Suitable
						  cleansing agents should also be provided to assure the effective removal of MC
						  from the skin.
C. Because of the hazardous nature of MC, contaminated
						  protective clothing should be placed in a regulated area designated by the
						  employer for removal of MC before the clothing is laundered or disposed of.VI.
						  Precautions for Safe Use, Handling, and Storage
A. Fire and Explosion Hazards:
MC has no flash point in a conventional closed tester,
						  but it forms flammable vapor-air mixtures at approximately 100 deg.C (212
						  deg.F), or higher. It has a lower explosion limit of 12%, and an upper
						  explosion limit of 19% in air. It has an autoignition temperature of 556.1
						  deg.C (1033 deg.F), and a boiling point of 39.8 deg.C (104 deg.F). It is
						  heavier than water with a specific gravity of 1.3. It is slightly soluble in
						  water.
B. Reactivity Hazards:
Conditions contributing to the instability of MC are
						  heat and moisture. Contact with strong oxidizers, caustics, and chemically
						  active metals such as aluminum or magnesium powder, sodium and potassium may
						  cause fires and explosions. Special precautions: Liquid MC will attack some
						  forms of plastics, rubber, and coatings.
C. Toxicity:
Liquid MC is painful and irritating if splashed in the
						  eyes or if confined on the skin by gloves, clothing, or shoes. Vapors in high
						  concentrations may cause narcosis and death. Prolonged exposure to vapors may
						  cause cancer or exacerbate cardiac disease.
D. Storage:
Protect against physical damage. Because of its
						  corrosive properties, and its high vapor pressure, MC should be stored in
						  plain, galvanized or lead lined, mild steel containers in a cool, dry, well
						  ventilated area away from direct sunlight, heat source and acute fire
						  hazards.
E. Piping Material:
All piping and valves at the loading or unloading
						  station should be of material that is resistant to MC and should be carefully
						  inspected prior to connection to the transport vehicle and periodically during
						  the operation.
F. Usual Shipping Containers:
Glass bottles, 5- and 55-gallon steel drums, tank cars,
						  and tank trucks. Note: This section addresses MC exposure in marine terminal
						  and long-shore employment only where leaking or broken packages allow MC
						  exposure that is not addressed through compliance with Article 14.
G. Electrical Equipment:
Electrical installations in Class I hazardous locations
						  as defined in Article 500 of the National Electrical Code, should be installed
						  according to Article 501 of the code; and electrical equipment should be
						  suitable for use in atmospheres containing MC vapors. See Flammable and
						  Combustible Liquids Code (NFPA No. 325M), Chemical Safety Data Sheet SD-86
						  (Manufacturing Chemists' Association, Inc.).
H. Fire Fighting:
When involved in fire, MC emits highly toxic and
						  irritating fumes such as phosgene, hydrogen chloride and carbon monoxide. Wear
						  breathing apparatus and use water spray to keep fire- exposed containers cool.
						  Water spray may be used to flush spills away from exposures. Extinguishing
						  media are dry chemical, carbon dioxide, foam. For purposes of compliance with
						  the Electrical Safety Orders, locations classified as hazardous due to the
						  presence of MC shall be Class I.
I. Spills and Leaks:
Persons not wearing protective equipment and clothing
						  should be restricted from areas of spills or leaks until cleanup has been
						  completed. If MC has spilled or leaked, the following steps should be
						  taken:
1. Remove all ignition sources.
2. Ventilate area of spill or leak.
3. Collect for reclamation or absorb in vermiculite,
						  dry sand, earth, or a similar material.
J. Methods of Waste Disposal:
Small spills should be absorbed onto sand and taken to
						  a safe area for atmospheric evaporation. Incineration is the preferred method
						  for disposal of large quantities by mixing with a combustible solvent and
						  spraying into an incinerator equipped with acid scrubbers to remove hydrogen
						  chloride gases formed. Complete combustion will convert carbon monoxide to
						  carbon dioxide. Care should be taken for the presence of phosgene.
K. You should not keep food, beverage, or smoking
						  materials, or eat or smoke in regulated areas where MC concentrations are above
						  the permissible exposure limits.
L. Portable heating units should not be used in
						  confined areas where MC is used.
M. Ask your supervisor where MC is used in your work
						  area and for any additional plant safety and health rules.VII. Medical
						  Requirements
Your employer is required to offer you the opportunity
						  to participate in a medical surveillance program if you are exposed to MC at
						  concentrations at or above the action level (12.5 ppm 8- hour TWA) for more
						  than 30 days a year or at concentrations exceeding the PELs (25 ppm 8- hour TWA
						  or 125 ppm 15-minute STEL) for more than 10 days a year. If you are exposed to
						  MC at concentrations over either of the PELs, your employer will also be
						  required to have a physician or other licensed health care professional ensure
						  that you are able to wear the respirator that you are assigned. Your employer
						  must provide all medical examinations relating to your MC exposure at a
						  reasonable time and place and at no cost to you.VIII. Monitoring and
						  Measurement Procedures
A. Exposure above the Permissible Exposure
						  Limit:
1. Eight-hour exposure evaluation: Measurements taken
						  for the purpose of determining employee exposure under this section are best
						  taken with consecutive samples covering the full shift. Air samples must be
						  taken in the employee's breathing zone.
2. Monitoring techniques: The sampling and analysis
						  under this section may be performed by collection of the MC vapor on two
						  charcoal adsorption tubes in series or other composition adsorption tubes, with
						  subsequent chemical analysis. Sampling and analysis may also be performed by
						  instruments such as real-time continuous monitoring systems, portable direct
						  reading instruments, or passive dosimeters as long as measurements taken using
						  these methods accurately evaluate the concentration of MC in employees'
						  breathing zones. OSHA method 80 is an example of a validated method of sampling
						  and analysis of MC. Copies of this method are available from OSHA or can be
						  downloaded from the Internet at http://www.osha.gov. The employer has the
						  obligation of selecting a monitoring method which meets the accuracy and
						  precision requirements of the standard under his or her unique field
						  conditions. The standard requires that the method of monitoring must be
						  accurate, to a 95 percent confidence level, to plus or minus 25 percent for
						  concentrations of MC at or above 25 ppm, and to plus or minus 35 percent for
						  concentrations at or below 25 ppm. In addition to OSHA method 80, there are
						  numerous other methods available for monitoring for MC in the workplace.
B. Since many of the duties relating to employee
						  exposure are dependent on the results of measurement procedures, employers must
						  assure that the evaluation of employee exposure is performed by a technically
						  qualified person.IX. Observation of Monitoring
Your employer is required to perform measurements that
						  are representative of your exposure to MC and you or your designated
						  representative are entitled to observe the monitoring procedure. You are
						  entitled to observe the steps taken in the measurement procedure, and to record
						  the results obtained. When the monitoring procedure is taking place in an area
						  where respirators or personal protective clothing and equipment are required to
						  be worn, you or your representative must also be provided with, and must wear,
						  protective clothing and equipment.X. Access To Information
A. Your employer is required to inform you of the
						  information contained in this Appendix. In addition, your employer must
						  instruct you in the proper work practices for using MC, emergency procedures,
						  and the correct use of protective equipment.
B. Your employer is required to determine whether you
						  are being exposed to MC. You or your representative has the right to observe
						  employee measurements and to record the results obtained. Your employer is
						  required to inform you of your exposure. If your employer determines that you
						  are being over exposed, he or she is required to inform you of the actions
						  which are being taken to reduce your exposure to within permissible exposure
						  limits.
C. Your employer is required to keep records of your
						  exposures and medical examinations. These records must be kept by the employer
						  for at least thirty (30) years.
D. Your employer is required to release your exposure
						  and medical records to you or your representative upon your request.
E. Your employer is required to provide labels and
						  safety data sheets (SDS) for all materials, mixtures or solutions composed of
						  greater than 0.1 percent MC. These materials, mixtures or solutions would be
						  classified and labeled in accordance with Section
						  5194.XI. Common Operations and
						  Controls
The following list includes some common operations in
						  which exposure to MC may occur and control methods which may be effective in
						  each case:
Operations
Controls
Use as solvent in paint and varnish removers;
								  manufacture of aerosols; cold cleaning and ultrasonic cleaning; and as a
								  solvent in furniture stripping.
General dilution ventilation; local
								  exhaust ventilation; personal protective equipment; substitution.
Use as solvent in vapor
								  degreasing.
Process enclosure; local exhaust ventilation; chilling
								  coils; substitution.
Use as a secondary refrigerant in air
								  conditioning and scientific testing.
General dilution ventilation;
								  local exhaust ventilation; personal protective equipment.
1. New
						  appendix A filed 8-4-97; operative 11-2-97 (Register 97, No. 32).
2.
						  Amendment of item X.E. filed 5-6-2013; operative 5-6-2013 pursuant to Labor
						  Code section
						  142.3(a)(4)(C).
						  Submitted to OAL for printing only pursuant to Labor Code section
						  142.3(a)(4)
						  (Register 2013, No. 19).
3. Amendment of item X.E. refiled
						  11-6-2013; operative 11-6-2013 pursuant to Labor Code section
						  142.3(a)(4)(C).
						  Submitted to OAL for printing only pursuant to Labor Code section
						  142.3(a)(4)
						  (Register 2013, No. 45).
4. Repealer of 11-6-2013 order by operation
						  of law 5-6-2014 pursuant to Labor Code 142.3 (Register 2014, No.
						  19).
5. Amendment of item X.E. filed 5-5-2014; operative 5-6-2014
						  pursuant to Government Code section
						  11343.4(b)(3)
						  (Register 2014, No. 19).
Note: Authority cited: Sections
							 142.3,
							 9020,
							 9030 and
							 9040, Labor
							 Code. Reference: Sections
							 142.3,
							 9004(d),
							 9009,
							 9020,
							 9031 and
							 9040, Labor
							 Code.