Disclaimer: These guidelines were developed under contract using generally accepted secondary sources. The protocol used by the contractor for surveying these data sources was developed by the National Institute for Occupational Safety and Health (NIOSH), the Occupational Safety and Health Administration (OSHA), and the Department of Energy (DOE). The information contained in these guidelines is intended for reference purposes only. None of the agencies have conducted a comprehensive check of the information and data contained in these sources. It provides a summary of information about chemicals that workers may be exposed to in their workplaces. The secondary sources used for supplements 111 and 1V were published before 1992 and 1993, respectively, and for the remainder of the guidelines the secondary sources used were published before September 1996. This information may be superseded by new developments in the field of industrial hygiene. Therefore readers are advised to determine whether new information is available.

OCCUPATIONAL SAFETY AND HEALTH GUIDELINE FOR 4,4'-METHYLENE BIS
(2-CHLOROANILINE)

INTRODUCTION

This guideline summarizes pertinent information about 4,4'-methylene bis (2-chloroaniline) for workers and employers as well as for physicians, industrial hygienists, and other occupational safety and health professionals who may need such information to conduct effective occupational safety and health programs. Recommendations may be superseded by new developments in these fields; readers are therefore advised to regard these recommendations as general guidelines and to determine whether new information is available.

SUBSTANCE IDENTIFICATION

* Formula

C(13)H(12)Cl(2)N(2)

* Structure

(For Structure, see paper copy)

* Synonyms

4,4' methylenebis (2-chlorobenzeamine); bis-amine; bis-amine A;

bisamine S; cyanaset; curalin M; curene 442; MOCA; MBOCA; DACPM

* Identifiers

1. CAS No.: 101-14-4

2. RTECS No.: CY1050000

3. Specific DOT number: None

4. Specific DOT label: None

* Appearance and odor

4,4'-Methylene bis (2-chloroaniline) is a colorless to yellow or light brown crystalline solid with a faint amine-like odor. It is commercially available in pellet form and can also be obtained in a liquid form.

CHEMICAL AND PHYSICAL PROPERTIES

* Physical data

1. Molecular weight: 267.17

2. Boiling point: Data not available.

3. Specific gravity: 1.44 at 4degreesC (39.2degreesF)

4. Vapor density: Data not available.

5. Melting point: 110degreesC (230degreesF)

6. Vapor pressure at 25degreesC (77degreesF): 1.0 * 10(-5) mm Hg

7. Solubility: Slightly soluble in water; soluble in diluted acids, ether, benzene, alcohol and soluble to varying degrees in most organic solvents.

8. Evaporation rate: Data not available.

* Reactivity

1. Conditions contributing to instability: None reported.

2. Incompatibilities: Contact between 4,4'-methylene bis (2- chloroaniline) and chemically-active metals such as potassium, sodium, magnesium and zinc should be avoided.

3. Hazardous decomposition products: Toxic gases such as chlorine and nitrogen oxides may be released in a fire involving 4,4'-methylene bis (2-chloroaniline).

4. Special precautions: None reported.

* Flammability

The National Fire Protection Association has not assigned a flammability rating to 4,4'-methylene bis (2-chloroaniline). Other sources rate 4,4'-methylene bis (2-chloroaniline) as slightly flammable when this substance is exposed to heat or open flame.

1. Flash point: Data not available.

2. Autoignition temperature: Data not available.

3. Flammable limits in air: Data not available.

4. Extinguishant: Use dry chemical, carbon dioxide, water spray, or foam to fight fires involving 4,4'-methylene bis (2-chloroaniline).

Fires involving 4,4'-methylene bis (2-chloroaniline) should be fought upwind from the maximum distance possible. Isolate the hazard area and deny access to unnecessary personnel. Firefighters should wear a full set of protective clothing and self-contained breathing apparatus when fighting fires involving 4,4'-methylene bis (2-chloroaniline).

EXPOSURE LIMITS

* OSHA PEL

The Occupational Safety and Health Administration (OSHA) does not currently regulate 4,4'-methylene bis (2-chloroaniline).

* NIOSH REL

The National Institute for Occupational Safety and Health (NIOSH) has established a recommended exposure limit (REL) for 4,4'-methylene bis (2-chloroaniline) of 0.003 milligram per cubic meter (mg/m(3)) of air, as a TWA for up to a 10-hour workday and a 40-hour workweek. NIOSH also assigns a "Skin" notation, which indicates that the cutaneous route of exposure, including mucous membranes and eyes, contributes to overall exposure. NIOSH considers 4,4'-methylene bis (2- chloroaniline) to be a potential human carcinogen [NIOSH 1992].

* ACGIH TLV

The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned 4,4'-methylene bis (2-chloroaniline) a threshold limit value (TLV) of 0.01 part per million (ppm) parts of air (0.11 mg/m(3)) as a TWA for a normal 8-hour workday and a 40-hour workweek. The ACGIH also assigns a "Skin" notation to 4,4'-methylene bis (2- chloroaniline). ACGIH considers 4,4'-methylene bis (2-chloroaniline) to be a suspected human carcinogen (A2 substance) [ACGIH 1994, p. 26].

* Rationale for Limits

The NIOSH limit is based on the risk of potential for cancer (liver and lung tumors in animals) [NIOSH 1992].

The ACGIH limit is based on the risk of cancer [ACGIH 1991, p. 992].

HEALTH HAZARD INFORMATION

* Routes of Exposure

Exposure to 4,4'-methylene bis (2-chloroaniline) can occur through inhalation, ingestion, and eye or skin contact.

* Summary of toxicology

1. Effects on Animals: 4,4'-Methylenebis (2-chloroaniline) is carcinogenic, is a mild skin irritant, and can affect the gastrointestinal system, liver, kidneys, and blood in experimental animals [ACGIH 1991]. 4,4'-Methylenebis (2-chloroaniline) caused mild skin irritation in guinea pigs and produced mild conjunctive irritation with no inflammation of the cornea or iris in rabbit eyes [ACGIH 1991]. 4,4'-Methylenebis (2-chloroaniline) is not a skin sensitizer [ACGIH 1991]. The oral LD(50) in rats ranged from 750 to 2,100 mg/kg [ACGIH 1991]. The dermal LD(50) in rabbits is greater than 5 gm/kg [NIOSH 1995]. Clinical signs associated with acute exposure to 4,4'-methylenebis (2-chloroaniline) include: inactivity, prostration, pallor, cyanosis, hypothermia, hematuria, stained perianal area, lacrimation, and weight loss. Pathological examination revealed distended hemorrhagic stomachs, distended bladders filled with a dark red fluid, pale and friable livers, and congested kidneys [ACGIH 1991]. In oral subchronic studies, similar signs of intoxication were observed. In addition, methemoglobinemia, polyuria, and glucosuria were observed [ACGIH 1991]. 4,4'-Methylenebis (2- chloroaniline) was genotoxic in multiple in vitro and in vivo test systems [IARC 1987; ACGIH 1991]. 4,4'-Methylenebis (2-chloroaniline) was carcinogenic in rats, mice, and dogs when administered orally [IARC 1987; ACGIH 1991]. Tumors associated with 4,4'-Methylenebis (2- chloroaniline) exposure included hemangiosarcomas and hepatomas in mice; lung, liver, mammary gland and zymbal gland tumors and hemangiosarcomas in rats; and urinary bladder tumors in dogs [IARC 1987; ACGIH 1991]. Based on these data, the International Agency for Research on Cancer (IARC) has concluded that there is sufficient evidence for the carcinogenicity of 4,4'-methylenebis (2- chloroaniline) in experimental animals [IARC 1987].

2. Effects on Humans: Based on evidence in animals, 4,4'-methylenebis (2-chloroaniline) is considered a potential human carcinogen [IARC 1987]. Exposure to 4,4'-methylenebis (2-chloroaniline) can affect the eyes and kidneys [ACGIH 1991]. It is considered to be a strongly suspected potential occupational bladder carcinogen [Rom 1992]. 4,4'- Methylenebis (2-chloroaniline) may have been a contributing agent or the primary causative agent leading to hematuria in workers exposed to unknown concentrations of a variety of contaminants [ACGIH 1991]. A worker splashed with hot liquid 4,4'-methylenebis (2-chloroaniline) had conjunctivitis in both eyes and experienced an upset stomach and proteinuria; the patient recovered rapidly without incident [ACGIH 1991]. IARC examined the carcinogenicity of 4,4'-methylenebis (2- chloroaniline) in humans and determined that there was inadequate evidence, however based on animal data, the substance is considered probably carcinogenic to humans (Group 2A) [IARC 1987].

* Signs and symptoms of exposure

1. Acute exposure: Acute exposure to 4,4'-methylenebis (2-chloroaniline) has caused conjunctivitis and proteinuria (by direct contact).

2. Chronic exposure: No signs or symptoms of chronic exposure to 4,4'- methylenebis (2-chloroaniline) have been reported in humans.

EMERGENCY MEDICAL PROCEDURES

* Emergency medical procedures: [NIOSH to supply]

5. Rescue: Remove an incapacitated worker from further exposure and implement appropriate emergency procedures (e.g., those listed on the Material Safety Data Sheet required by OSHA's Hazard Communication Standard [29 CFR 1910.1200]). All workers should be familiar with emergency procedures, the location and proper use of emergency equipment, and methods of protecting themselves during rescue operations.

EXPOSURE SOURCES AND CONTROL METHODS

The following operations may involve 4,4'-methylene bis(2-chloroaniline) and lead to worker exposures to this substance:

* The manufacture and transportation of 4,4'-methylene bis (2- chloroaniline)

* Use in the manufacture of gun mounts, jet engine turbine blades,radar systems, and home appliances

* Use as a curing agent

Methods that are effective in controlling worker exposures to 4,4'- methylene bis (2-chloroaniline), depending on the feasibility of implementation, are as follows:

* Process enclosure
* Local exhaust ventilation
* General dilution ventilation
* Personal protective equipment

Workers responding to a release or potential release of a hazardous substance must be protected as required by paragraph (q) of OSHA's Hazardous Waste Operations and Emergency Response Standard [29 CFR 1910.120].

Good sources of information about control methods are as follows:

1. ACGIH [1992]. Industrial ventilation--a manual of recommended practice. 21st ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

2. Burton DJ [1986]. Industrial ventilation--a self study companion. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

3. Alden JL, Kane JM [1982]. Design of industrial ventilation systems. New York, NY: Industrial Press, Inc.

4. Wadden RA, Scheff PA [1987]. Engineering design for control of workplace hazards. New York, NY: McGraw-Hill.

5. Plog BA [1988]. Fundamentals of industrial hygiene. Chicago, IL: National Safety Council.

MEDICAL SURVEILLANCE

OSHA is currently developing requirements for medical surveillance. When these requirements are promulgated, readers should refer to them for additional information and to determine whether employers whose employees are exposed to 4,4'-methylene bis (2-chloroaniline) are required to implement medical surveillance procedures.

* Medical Screening

Workers who may be exposed to chemical hazards should be monitored in a systematic program of medical surveillance that is intended to prevent occupational injury and disease. The program should include education of employers and workers about work-related hazards, early detection of adverse health effects, and referral of workers for diagnosis and treatment. The occurrence of disease or other work- related adverse health effects should prompt immediate evaluation of primary preventive measures (e.g., industrial hygiene monitoring, engineering controls, and personal protective equipment). A medical surveillance program is intended to supplement, not replace, such measures. To detect and control work-related health effects, medical evaluations should be performed (1) before job placement, (2) periodically during the term of employment, and (3) at the time of job transfer or termination.

* Preplacement medical evaluation

Before a worker is placed in a job with a potential for exposure to 4,4'-methylene bis (2-chloroaniline), a licensed health care professional should evaluate and document the worker's baseline health status with thorough medical, environmental, and occupational histories, a physical examination, and physiologic and laboratory tests appropriate for the anticipated occupational risks. These should concentrate on the function and integrity of the liver, kidneys, hematopoietic system, and respiratory system. Medical surveillance for respiratory disease should be conducted using the principles and methods recommended by the American Thoracic Society.

A preplacement medical evaluation is recommended to assess medical conditions that may be aggravated or may result in increased risk when a worker is exposed to 4,4'-methylene bis (2-chloroaniline) at or below the prescribed exposure limit. The health care professional should consider the probable frequency, intensity, and duration of exposure as well as the nature and degree of any applicable medical condition. Such conditions (which should not be regarded as absolute contraindications to job placement) include a history and other findings consistent with diseases of the liver, kidneys, hematopoietic system, or respiratory system.

* Periodic medical evaluations

Occupational health interviews and physical examinations should be performed at regular intervals during the employment period, as mandated by any applicable Federal, State, or local standard. Where no standard exists and the hazard is minimal, evaluations should be conducted every 3 to 5 years or as frequently as recommended by an experienced occupational health physician. Additional examinations may be necessary if a worker develops symptoms attributable to 4,4'- methylene bis (2-chloroaniline) exposure. The interviews, examinations, and medical screening tests should focus on identifying the adverse effects of 4,4'-methylene bis (2-chloroaniline) on the liver, kidneys, hematopoietic system, or respiratory system. Current health status should be compared with the baseline health status of the individual worker or with expected values for a suitable reference population.

* Termination medical evaluations

The medical, environmental, and occupational history interviews, the physical examination, and selected physiologic or laboratory tests that were conducted at the time of placement should be repeated at the time of job transfer or termination to determine the worker's medical status at the end of his or her employment. Any changes in the worker's health status should be compared with those expected for a suitable reference population.

* Biological monitoring

Biological monitoring involves sampling and analyzing body tissues or fluids to provide an index of exposure to a toxic substance or metabolite. No biological monitoring test acceptable for routine use has yet been developed for 4,4'-methylene bis (2-chloroaniline).

WORKPLACE MONITORING AND MEASUREMENT

Determination of a worker's exposure to airborne 4,4'-methylene bis (2- chloroaniline) is made using coated glass fiber filters (37 mm) in a 3- piece cassette. The filter coating is sulfuric acid. Samples are collected at a maximum flow rate of 1 liter/minute until a maximum collection volume of 100 liters is reached. Analysis is conducted by gas chromatography using an electron capture detector (GC/ECD). This method (OSHA 71) is described in the OSHA Computerized Information System [OSHA 1994] and is fully validated.

PERSONAL HYGIENE PROCEDURES

If 4,4'-methylene bis (2-chloroaniline) contacts the skin, workers should immediately wash the affected areas with large amounts of soap and water.

Clothing contaminated with 4,4'-methylene bis (2-chloroaniline) should be removed immediately, and provisions should be made for the safe removal of the chemical from the clothing. Persons laundering the clothes should be informed of the hazardous properties of 4,4'-methylene bis (2- chloroaniline).

A worker who handles 4,4'-methylene bis (2-chloroaniline) should thoroughly wash hands, forearms, and face with soap and water before eating, using tobacco products, using toilet facilities, applying cosmetics, or taking medication.

Workers should not eat, drink, use tobacco products, apply cosmetics, or take medication in areas where 4,4'-methylene bis (2-chloroaniline) or a solution containing 4,4'-methylene bis (2-chloroaniline) is handled, processed, or stored.

STORAGE

4,4'-Methylene bis (2-chloroaniline) should be stored in a cool, dry, well- ventilated area in tightly sealed containers that are labeled in accordance with OSHA's Hazard Communication Standard [29 CFR 1910.1200]. Containers of 4,4'-methylene bis (2-chloroaniline) should be protected from physical damage and should be stored separately from chemically-active metals such as potassium, sodium, magnesium and zinc.

SPILLS AND LEAKS

In the event of a spill or leak involving 4,4'-methylene bis (2- chloroaniline), persons not wearing protective equipment and clothing should be restricted from contaminated areas until cleanup has been completed. The following steps should be undertaken following a spill or leak:

1. If a spill of molten 4,4'-methylene bis (2-chloroaniline) results in potential high exposures, evacuate the area and wait for the material to solidify before returning to the area.

2. Caution should be taken not to generate dusty conditions during the cleanup of this material.

3. Collect the powdered material in the most convenient and safe manner possible and deposit it into a suitable container for disposal.

SPECIAL REQUIREMENTS

U.S. Environmental Protection Agency (EPA) requirements for emergency planning, reportable quantities of hazardous releases, community right-to- know, and hazardous waste management may change over time. Users are therefore advised to determine periodically whether new information is available.

* Emergency planning requirements

4,4'-Methylene bis (2-chloroaniline) is not subject to EPA emergency planning requirements under the Superfund Amendments and Reauthorization Act (SARA) (Title III) in 42 USC 11022.

* Reportable quantity requirements for hazardous releases

A hazardous substance release is defined by EPA as any spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, or disposing into the environment (including the abandonment or discarding of contaminated containers) of hazardous substances. In the event of a release that is above the reportable quantity for that chemical, employers are required to notify the proper Federal, State, and local authorities [40 CFR 355.40].

The reportable quantity of 4,4'-methylene bis (2-chloroaniline) is 10 pounds. If an amount equal to or greater than this quantity is released within a 24-hour period in a manner that will expose persons outside the facility, employers are required to do the following:

- Notify the National Response Center immediately at (800) 424-8802 or at (202) 426-2675 in Washington, D.C. [40 CFR 302.6].

* Community right-to-know requirements

Employers who own or operate facilities in SIC codes 20 to 39 that employ 10 or more workers and that manufacture 25,000 pounds or more of 4,4'-methylene bis(2-chloroaniline) per calendar year or otherwise use 10,000 pounds or more of 4,4'-methylene bis(2-chloroaniline) per calendar year are required by EPA [40 CFR Part 372.30] to submit a Toxic Chemical Release Inventory form (Form R) to EPA reporting the amount of 4,4'-methylene bis(2-chloroaniline) emitted or released from their facility annually.

* Hazardous waste management requirements

EPA considers a waste to be hazardous if it exhibits any of the following characteristics: ignitability, corrosivity, reactivity, or toxicity as defined in 40 CFR 261.21-261.24. Under the Resource Conservation and Recovery Act (RCRA) [40 USC 6901 et seq.], EPA has specifically listed many chemical wastes as hazardous. 4,4'-Methylene bis (2-chloroaniline) is listed as a hazardous waste under RCRA and has been assigned EPA Hazardous Waste No. U158. It is approved for land disposal after treatment and only if the concentration of 4,4'- methylene bis (2-chloroaniline) in the waste or treatment residual does not exceed 35 mg/kg.

Providing detailed information about the removal and disposal of specific chemicals is beyond the scope of this guideline. The U.S. Department of Transportation, EPA, and State and local regulations should be followed to ensure that removal, transport, and disposal of this substance are conducted in accordance with existing regulations. To be certain that chemical waste disposal meets EPA regulatory requirements, employers should address any questions to the RCRA hotline at (703) 412-9810 (in the Washington, D.C. area) or toll-free at (800) 424-9346 (outside Washington, D.C.). In addition, relevant State and local authorities should be contacted for information on any requirements they may have for the waste removal and disposal of this substance.

RESPIRATORY PROTECTION

* Conditions for respirator use

Good industrial hygiene practice requires that engineering controls be used where feasible to reduce workplace concentrations of hazardous materials to the prescribed exposure limit. However, some situations may require the use of respirators to control exposure. Respirators must be worn if the ambient concentration of 4,4'-methylene bis(2- chloroaniline) exceeds prescribed exposure limits. Respirators may be used (1) before engineering controls have been installed, (2) during work operations such as maintenance or repair activities that involve unknown exposures, (3) during operations that require entry into tanks or closed vessels, and (4) during emergencies. Workers should only use respirators that have been approved by NIOSH and the Mine Safety and Health Administration (MSHA).

* Respiratory protection program

Employers should institute a complete respiratory protection program that, at a minimum, complies with the requirements of OSHA's Respiratory Protection Standard [29 CFR 1910.134]. Such a program must include respirator selection, an evaluation of the worker's ability to perform the work while wearing a respirator, the regular training of personnel, respirator fit testing, periodic workplace monitoring, and regular respirator maintenance, inspection, and cleaning. The implementation of an adequate respiratory protection program (including selection of the correct respirator) requires that a knowledgeable person be in charge of the program and that the program be evaluated regularly. For additional information on the selection and use of respirators and on the medical screening of respirator users, consult the latest edition of the NIOSH Respirator Decision Logic [NIOSH 1987b] and the NIOSH Guide to Industrial Respiratory Protection [NIOSH 1987a].

PERSONAL PROTECTIVE EQUIPMENT

Workers should use appropriate personal protective clothing and equipment that must be carefully selected, used, and maintained to be effective in preventing skin contact with 4,4'-methylene bis(2-chloroaniline). The selection of the appropriate personal protective equipment (PPE) (e.g., gloves, sleeves, encapsulating suits) should be based on the extent of the worker's potential exposure to 4,4'-methylene bis(2-chloroaniline). The resistance of 4H (PE/EVAL) to permeation by 4,4'-methylene bis (2- chloroaniline) is shown below:

To evaluate the use of this or other PPE materials with 4,4'-methylene bis (2-chloroaniline), users should consult the best available performance data and manufacturers' recommendations. Significant differences have been demonstrated in the chemical resistance of generically similar PPE materials (e.g., butyl) produced by different manufacturers. In addition, the chemical resistance of a mixture may be significantly different from that of any of its neat components.

Any chemical-resistant clothing that is used should be periodically evaluated to determine its effectiveness in preventing dermal contact. Safety showers and eye wash stations should be located close to operations that involve 4,4'-methylene bis(2-chloroaniline).

Splash-proof chemical safety goggles or face shields (20 to 30 cm long, minimum) should be worn during any operation in which a solvent, caustic, or other toxic substance may be splashed into the eyes.

In addition to the possible need for wearing protective outer apparel (e.g., aprons, encapsulating suits), workers should wear work uniforms, coveralls, or similar full-body coverings that are laundered each day. Employers should provide lockers or other closed areas to store work and street clothing separately. Employers should collect work clothing at the end of each work shift and provide for its laundering. Laundry personnel should be informed about the potential hazards of handling contaminated clothing and instructed about measures to minimize their health risk.

Protective clothing should be kept free of oil and grease and should be inspected and maintained regularly to preserve its effectiveness.

Protective clothing may interfere with the body's heat dissipation, especially during hot weather or during work in hot or poorly ventilated work environments.

REFERENCES

ACGIH [1991]. Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

ACGIH [1994]. 1994-1995 Threshold limit values for chemical substances and physical agents and biological exposure indices. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

ATS [1987]. Standardization of spirometry -- 1987 update. American Thoracic Society. Am Rev Respir Dis 136:1285-1296.

CFR. Code of Federal regulations. Washington, DC: U.S. Government Printing Office, Office of the Federal Register.

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IARC [1987]. IARC monographs on the evaluation of carcinogenic risk of chemicals to man. Supplement 7. Lyon, France: World Health Organization, International Agency for Research on Cancer.

Mickelsen RL, Hall RC [1987]. A breakthrough time comparison of nitrile and neoprene glove materials produced by different glove manufacturers. Am Ind Hyg Assoc J 48(11): 941-947.

Mickelsen RL, Hall RC, Chern RT, Myers JR [1991]. Evaluation of a simple weight-loss method for determining the permeation of organic liquids through rubber films. Am Ind Hyg Assoc J 52(10): 445-447.

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NIOSH [1987b]. NIOSH respirator decision logic. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 87-108.

NIOSH [1992]. Recommendations for occupational safety and health: Compendium of policy documents and statements. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 92-100.

NIOSH [1994]. NIOSH pocket guide to chemical hazards. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-116.

NIOSH [1995]. Registry of toxic effects of chemical substances: 4,4'- Methylene bis(2-chloroaniline). Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, Division of Standards Development and Technology Transfer, Technical Information Branch.

NJDH [1987]. Hazardous substance fact sheet: 4,4'-Methylene bis(2- chloroaniline). Trenton, NJ: New Jersey Department of Health.

NLM [1995]. Hazardous substances data bank: 4,4'-Methylene bis(2- chloroaniline). Bethesda, MD: National Library of Medicine.

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Rom WN [1992]. Environmental and occupational medicine. 2nd ed. Boston, MA: Little, Brown and Company.

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