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 This information may be superseded by new developments in the field of industrial hygiene.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 ETHYL BROMIDE

INTRODUCTION

This guideline summarizes pertinent information about ethyl bromide 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 Recommendations may be superseded by new developments in these fields; readers are therefore advised to regard these recommendations as general guidelines and to determine whether new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(2)H(5)Br

* Structure

(For Structure, see paper copy)

* Synonyms

Bromoethane, monobromoethane, bromic ether, hydrobromic ether, halon 2001

* Identifiers

1. CAS No.: 74-96-4

2. RTECS No.: KH6475000

3. DOT UN: 1891 58

4. DOT label: Poison

* Appearance and odor

Ethyl bromide is a colorless, highly volatile, flammable liquid that turns yellowish on exposure to light and air and has an ether-like odor. The air odor threshold concentration for ethyl bromide is 3.1 parts per million (ppm) parts of air.

CHEMICAL AND PHYSICAL PROPERTIES

* Physical data

1. Molecular weight: 108.98

2. Boiling point (at 760 mm Hg): 38.4 degrees C (101.12 degrees F)

3. Specific gravity: 1.46 at 20 degrees C (68 degrees F)

4. Vapor density: 3.76

5. Melting point: -119 degrees C (-182 degrees F)

6. Vapor pressure at 20 degrees C (68 degrees F): 375 mm Hg

7. Solubility: Slightly soluble in water; soluble in ethanol, chloroform, diethyl ether, and other organic solvents.

8. Evaporation rate: Data not available.

* Reactivity

1. Conditions contributing to instability: Heat, sparks, and open flame.

2. Incompatibilities: Contact between ethyl bromide and chemically active metals such as sodium, potassium, calcium, powdered aluminum, zinc, and magnesium or strong oxidizing agents should be avoided.

3. Hazardous decomposition products: Toxic and corrosive gases and vapors (such as carbon monoxide) may be released in a fire involving ethyl bromide or when ethyl bromide reacts with water or steam. Ethyl bromide readily decomposes into hydrobromic acid, particularly in the presence of hot surfaces or open flames.

4. Special precautions: Liquid ethyl bromide attacks some forms of plastic, rubber, and coatings.

* Flammability

The National Fire Protection Association has assigned a flammability rating of 1 (slight fire hazard) to ethyl bromide.

1. Flash point: Less than -20 degrees C (-4 degrees F) (closed cup)

2. Autoignition temperature: 511 degrees C (952 degrees F)

3. Flammable limits in air (percent by volume): Lower, 6.8; upper, 8.0

4. Extinguishant: For small fires use dry chemical, carbon dioxide, water spray, or regular foam. Use water spray, fog, or regular foam to fight large fires involving ethyl bromide.

Fires involving ethyl bromide should be fought upwind from the maximum distance possible. Keep unnecessary people away; isolate the hazard area and deny entry. Emergency personnel should stay out of low areas and ventilate closed spaces before entering. Firefighters should wear a full set of chemical protective clothing and self-contained breathing apparatus when fighting fires involving ethyl bromide.

EXPOSURE LIMITS

The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for ethyl bromide is 200 ppm (890 milligrams per cubic meter (mg/m(3))) as an 8-hour time-weighted average (TWA) concentration [29 CFR 1910.1000, Table Z-1].

* NIOSH REL

* The National Institute for Occupational Safety and Health has not established a recommended exposure limit for ethyl bromide.

* ACGIH TLV

The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned ethyl bromide a threshold limit value (TLV) of 5 ppm (22 mg/m(3)) as a TWA for a normal 8-hour workday and a 40-hour workweek. The ACGIH also considers ethyl bromide a suspected human carcinogen (A2 substance). The ACGIH assigns a "Skin" notation, which indicates that the cutaneous route of exposure (including mucous membranes and eyes) contributes to overall exposure [ACGIH 1994, p. 21].

* Rationale for Limits

The ACGIH limit is based on analogy to the toxicity of methyl bromide and on the risk of cancer, liver, kidney, cardiac, and other systemic effects [ACGIH 1991, p. 589].

HEALTH HAZARD INFORMATION

* Routes of Exposure

Exposure to ethyl bromide can occur through inhalation, ingestion, and eye or skin contact [Sittig 1991].

* Summary of toxicology

1. Effects on Animals: Ethyl bromide is a central nervous system depressant, and an eye, skin, lung and kidney toxin. The oral LD(50) in rats is 1,350 mg/kg; the lowest lethal inhalation concentration in rats is 148,000 ppm for 15 minutes [Genium 1987]. Acute inhalation exposure of guinea pigs to concentrations of 140,000 ppm ethyl bromide for 10 minutes caused death within several days [ACGIH 1991]; and exposure to concentrations of 50,000 ppm for 98 minutes caused death within 1 hour [Hathaway et al. 1991]. Lung injury occurred after exposure to 60,000 ppm ethyl bromide for 10 minutes, and dizziness and congestion of the lungs and liver occurred after exposure to 24,000 ppm for 10 minutes [Clayton and Clayton 1982]. Ethyl bromide is irritating to the eyes when the liquid is instilled into rabbit eyes; it causes necrosis when in contact with the skin [Hathaway et al. 1991]. Ethyl bromide did not increase the incidence of pulmonary tumors in strain A mice receiving intraperitoneal doses of 1, 1/2, and 1/5 of the maximum tolerated dose, once per week for 24 weeks. The authors suggest that the inactivity of ethyl bromide may be due to metabolic inactivation when administered intraperitoneally [ACGIH 1991]. However, a variety of carcinogenic effects (dependent on species and sex) were observed in a 2-year inhalation study at 100, 200 or 400 ppm for 6 hours/day 5 days/week. There was some evidence of carcinogenic activity in male F344/N rats, as evidenced by increased incidences of pheochromocytomas of the adrenal gland. In addition, neoplasms of the brain and the lung are suspected to have been related to exposure to ethyl bromide. For female F344/N rats, there was equivocal evidence of carcinogenic activity, as demonstrated by marginally increased incidences of neoplasms of the brain and the lung. In the high-dose rats, alveolar epithelia hyperplasia was increased, as were the incidences of epithelial hyperplasia and squamous metaplasia of the nasal cavity. In male B6C3F1 mice, there was equivocal evidence of carcinogenic activity, as indicated by the marginally increased incidences of neoplasms of the lung. There was clear evidence of carcinogenic activity for female B6C3F1 mice, as evidenced by neoplasms of the uterus [Hathaway et al. 1991]. Ethyl bromide is mutagenic in bacterial test systems.

2. Effects on Humans: Ethyl bromide is a central nervous system depressant; an eye, skin, and respiratory irritant; and a liver and kidney toxin in humans. Use of ethyl bromide as a general anesthetic (at concentrations of 100,000 ppm) produced respiratory irritation as well as immediate fatalities due to respiratory or cardiac arrest. Delayed deaths also occurred; pathologic changes at autopsy included pulmonary edema and fatty degeneration of the liver, kidney, and heart [Hathaway et al. 1991; Clayton and Clayton 1982]. Volunteers exposed to 6,500 ppm for 5 minutes reported vertigo, headache, and eye irritation [Hathaway et al. 1991]. One case of complete blindness is reported to have resulted from the anesthetic use of ethyl bromide. Other ocular complications included conjunctival hyperemia with occasional hemorrhage [NLM 1992].

* Signs and symptoms of exposure

1. Acute exposure: Signs and symptoms of acute exposure to ethyl bromide include irritation of the upper respiratory tract and, at high concentrations, drowsiness, incoordination, and narcosis. Contact of the liquid with the skin causes burns, and liquid splashed in the eye causes irritation. Acute exposure to very high concentrations of ethyl bromide may cause damage to the kidney, liver, and heart.

2. Chronic exposure: No signs or symptoms of chronic exposure to ethyl bromide 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 ethyl bromide and lead to worker exposures to this substance:

* The manufacture and transportation of ethyl bromide

* Used as an alkylating or ethylating agent in organic synthesis and gasoline; in the manufacture of pharmaceuticals and, to a lesser extent, of chemicals, dyes, and perfumes

* Used as an extraction solvent for fats, waxes, and resins

* Used for extinguishing fires and as a refrigerant

* Used as a local surface anesthetic for minor surgery and neuralgic pain

* Used as a fumigant for grain and fruit

Methods that are effective in controlling worker exposures to ethyl bromide, 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 ethyl bromide 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 ethyl bromide, 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 skin, respiratory system, heart, liver, and kidneys. 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 ethyl bromide 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 skin, respiratory system, heart, liver, or kidneys.

* 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 ethyl bromide exposure. The interviews, examinations, and medical screening tests should focus on identifying the adverse effects of ethyl bromide on the skin, respiratory system, heart, liver, or kidneys. 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. Because occupational exposure to ethyl bromide may cause diseases with prolonged latent periods, the need for medical surveillance may extend well beyond the termination of employment.

* 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 ethyl bromide.

WORKPLACE MONITORING AND MEASUREMENT

Determination of a worker's exposure to airborne ethyl bromide is made using a charcoal tube (100/50 mg sections, 20/40 mesh). Samples are collected at a maximum flow rate of 0.2 liter/minute (STEL, or TWA) until a maximum collection volume of 3 liters (STEL) or 4 liters (TWA) is reached. The sample is then treated with isopropanol. Analysis is conducted by gas chromatography using a flame ionization detector (GC/FID). This method is fully validated and is described in the OSHA Computerized Information System [OSHA 1994] and in NIOSH Method No. 1011 [NIOSH 1994b].

PERSONAL HYGIENE PROCEDURES

If ethyl bromide contacts the skin, workers should flush the affected areas immediately with plenty of water for at least 15 minutes, followed by washing with soap and water.

Clothing contaminated with ethyl bromide 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 ethyl bromide, particularly its potential for causing irritation.

A worker who handles ethyl bromide 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 ethyl bromide or a solution containing ethyl bromide is handled, processed, or stored.

STORAGE

Ethyl bromide 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]. Outside or detached storage is preferred. The storage area must meet OSHA requirements for Class 1A flammable liquids. Containers of ethyl bromide should be protected from physical damage, direct sunlight, and ignition sources, and should be stored separately from chemically active metals such as sodium, potassium, calcium, powdered aluminum, zinc, and magnesium or strong oxidizing agents should be avoided.

SPILLS AND LEAKS

In the event of a spill or leak involving ethyl bromide, 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. Notify safety personnel.

2. Remove all sources of heat and ignition.

3. Ventilate potentially explosive atmospheres.

4. Do not touch the spilled material; stop the leak if it is possible to do so without risk.

5. Use non-sparking tools.

6. For small liquid spills, take up with sand or other noncombustible absorbent material and place into closed containers for later disposal.

7. For large liquid spills, build dikes far ahead of the spill to contain the ethyl bromide for later reclamation or 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

Ethyl bromide 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].

Employers are not required by the emergency release notification provisions in 40 CFR Part 355.40 to notify the National Response Center of an accidental release of ethyl bromide; there is no reportable quantity for this substance.

* Community right-to-know requirements

Employers are not required by EPA in 40 CFR Part 372.30 to submit a Toxic Chemical Release Inventory form (Form R) to EPA reporting the amount of ethyl bromide 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. Although ethyl bromide is not specifically listed as a hazardous waste under RCRA, EPA requires employers to treat waste as hazardous if it exhibits any of the characteristics discussed above.

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 ethyl bromide 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 ethyl bromide. 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 ethyl bromide. The resistance of various materials to permeation by ethyl bromide is shown below:

(*) Not recommended, degradation may occur

To evaluate the use of these PPE materials with ethyl bromide, 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 ethyl bromide.

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.

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