Disclaimer: The information contained in these guidelines is intended for reference purposes only. It provides a summary of information about chemicals that workers may be exposed to in their workplaces. The information may be superseded by new developments in the field of industrial hygiene. Readers are therefore advised to regard these recomendations as general guidelines and to determine whether new information is available.

OCCUPATIONAL SAFETY AND HEALTH GUIDELINE FOR TETRAMETHYL LEAD

INTRODUCTION

This guideline summarizes pertinent information about tetramethyl lead (measured as lead) 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 Recommendations may be superseded by new developments; readers are therefore advised to regard these recommendations as general guidelines and to determine periodically whether new information is available.

SUBSTANCE IDENTIFICATION

* Formula

(CH(3))(4)Pb

* Structure

(For Structure, see paper copy)

* Synonyms

Tetramethylplumbane; TML.

* Identifiers

1. CAS: 75-74-1.

2. RTECS: TP4725000.

3. DOT UN: 1649 56 (motor fuel antiknock mixture).

4. DOT label: Poison.

* Appearance and odor

Tetramethyl lead is a flammable, colorless liquid with a slightly sweet odor; the commercial product is often dyed red, orange, or blue. Tetramethyl lead is frequently mixed with smaller amounts of ethylene dibromide, ethylene dichloride, dyes, kerosene, stabilizers, and inert substances.

CHEMICAL AND PHYSICAL PROPERTIES

* Physical data

1. Molecular weight: 267.33.

2. Boiling point (10 torr): 110 degrees C (230 degrees F).

3. Specific gravity (water = 1): 2.0 at 20 degrees C (68 degrees F).

4. Vapor density (air = 1 at boiling point of tetramethyl lead): 6.5.

5. Melting point: -27.5 degrees C (-17.5 degrees F).

6. Vapor pressure at 20 degrees C (68 degrees F): 22.5 torr.

7. Solubility: Insoluble in water; soluble in most organic solvents, including alcohol, benzene, and petroleum ether.

8. Evaporation rate: Data not available.

* Reactivity

1. Conditions contributing to instability: Temperatures above 100 degrees C (212 degrees F) cause decomposition and the development of pressure that may cause containers to burst.

2. Incompatibilities: Contact of tetramethyl lead with tetrachlorotrifluoromethyl phosphorus or with strong oxidizers, such as sulfuryl chloride or potassium permanganate, may cause fires and explosions.

3. Hazardous decomposition products: Toxic gases and particulates (such as lead fumes and carbon monoxide) may be released in a fire involving tetramethyl lead.

4. Special precautions: None reported.

* Flammability

The National Fire Protection Association has assigned a flammability rating of 3 (severe fire hazard) to tetramethyl lead.

1. Flash point: 38 degrees C (100 degrees F) (open cup).

2. Autoignition temperature: Data not available.

3. Flammable limits in air: Data not available.

4. Extinguishant: Use water spray, dry chemical, foam, or carbon dioxide for tetramethyl lead fires that do not involve containers. If a leak or spill has not ignited, water spray may be used to disperse vapors and to protect persons attempting to stop the leak.

Fires involving tetramethyl lead should be fought upwind and from the maximum distance possible. Keep unnecessary people away; isolate hazard area and deny entry. Emergency personnel should stay out of low areas and ventilate closed spaces before entering. Containers of tetramethyl lead may explode in the heat of the fire and should be moved from the fire area if it is possible to do so safely. If this is not possible, cool containers from the sides with water until well after the fire is out. Stay away from the ends of containers. Dikes should be used to contain fire-control water for later disposal. Firefighters should wear a full set of protective clothing, including a self-contained breathing apparatus, when fighting fires involving tetramethyl lead. Chemical protective clothing that is specifically recommended for tetramethyl lead may not provide thermal protection unless so stated by the clothing manufacturer. Firefighters' protective clothing is not effective against fires involving tetramethyl lead.

* Warning properties

No quantitative information is available on the odor threshold for tetramethyl lead.

* Eye irritation properties

Tetramethyl lead is not reported to be an eye irritant.

EXPOSURE LIMITS

The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for tetramethyl lead (measured as lead) is 0.075 milligram per cubic meter (mg/m(3)) of air as an 8-hour time-weighted average (TWA) concentration. The OSHA PEL also bears a "Skin" notation, which indicates that the cutaneous route of exposure (including mucous membranes and eyes) contributes to overall exposure [29 CFR 1910.1000, Table Z-1-A]. The National Institute for Occupational Safety and Health (NIOSH) has not issued a recommended exposure limit (REL) for tetramethyl lead; however, NIOSH concurs with the PEL established for this substance by OSHA [NIOSH 1988]. The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned tetramethyl lead (measured as lead) a threshold limit value (TLV) of 0.15 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 tetramethyl lead [ACGIH 1991, p. 35]. The ACGIH limit is based on the risk of central nervous system effects associated with exposure to tetramethyl lead [ACGIH 1986, p. 565].

HEALTH HAZARD INFORMATION

* Routes of exposure

Exposure to tetramethyl lead can occur via inhalation, ingestion, and eye or skin contact.

* Summary of toxicology

1. Effects on Animals: Tetramethyl lead is toxic to the central nervous system. The oral LD(50) in rats is 105 mg/kg, and the LC(50) in mice is 8500 mg/kg for 30 minutes [RTECS 1989]. The lowest lethal dermal dose in rabbits is 3391 mg/kg [RTECS 1989]. In acute inhalation studies, tetramethyl lead is more toxic than tetraethyl lead in dogs and mice, but in rats and monkeys, tetraethyl lead is more toxic [Hathaway, Proctor, Hughes, and Fischman 1991, p. 539]. Rats exposed to lethal concentrations of tetramethyl lead developed tremors, hyperactivity, and convulsions before death; at autopsy, histologic changes were observed in the central nervous system and liver [Hathaway, Proctor, Hughes, and Fischman 1991, p. 539]. Rhesus monkeys given intravenous doses (1.2, 2.4, or 6 mg/kg/day) of tetramethyl lead developed gastrointestinal disturbances, abnormal reflexes, muscle tremors, and decreased brain cholinesterase levels [HSDB 1989]. Administered to rats at a dose of 80 to 112 mg/kg on days 9 to 11 of pregnancy, tetramethyl lead caused an increase in post-implantation mortality and skeletal abnormalities among the offspring [RTECS 1989].

2. Effects on Humans: Tetramethyl lead affects the central nervous system in humans. Several cases of acute poisoning caused by exposure to tetramethyl lead have occurred in the occupational setting; the principal effect of such exposures is encephalopathy [Hathaway, Proctor, Hughes, and Fischman 1991, p. 539]. Accidental human exposure to a high (not further specified) level of liquid tetramethyl lead for a period of 5 minutes caused no signs or symptoms of lead poisoning [Hathaway, Proctor, Hughes, and Fischman 1991, p. 539]. In a case of massive skin exposure to tetramethyl lead, the victim showed no signs or symptoms of lead poisoning [Gosselin, Smith, and Hodge 1984, p. III-232].

* Signs and symptoms of exposure

1. Acute exposure: The signs and symptoms of acute exposure to tetramethyl lead reflect central nervous system effects, including insomnia, fatigue, restlessness, bad dreams, irritability, weakness, and tremors.

2. Chronic exposure: No signs or symptoms of chronic exposure to tetramethyl lead have been reported in humans.

* Emergency procedures:

In the event of an emergency, the rescuer should don appropriate personal protective equipment, remove the victim from further exposure, send for medical assistance, and initiate the following emergency procedures:

1. Eye exposure: If tetramethyl lead or a solution containing this substance gets into the eyes, immediately flush the eyes with large amounts of water for a minimum of 15 minutes, lifting the lower and upper lids occasionally. If irritation persists, get medical attention as soon as possible.

2. Skin exposure: If tetramethyl lead or a solution containing this substance contacts the skin, the contaminated skin should be flushed with large amounts of water for at least 15 minutes, followed by washing with soap and water. If irritation persists, get medical attention.

3. Inhalation: If tetramethyl lead vapors are inhaled, move the victim at once to fresh air and get medical care as soon as possible. If the victim is not breathing, perform cardiopulmonary resuscitation; if breathing is difficult, give oxygen. Keep the victim warm and quiet until medical help arrives.

4. Ingestion: If tetramethyl lead or a solution containing this substance is ingested, give the victim several glasses of water to drink and then induce vomiting by having the victim touch the back of the throat with the finger or by giving syrup of ipecac as directed on the package. Do not force an unconscious or convulsing person to drink liquids or to vomit. Get medical help immediately. Keep the victim warm and quiet until medical help arrives.

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 tetramethyl lead and lead to worker exposures to this substance:

• Manufacture and use of premium and aviation gasolines containing alkyl lead anti-knock additives
• Use in laboratory engine testing

Methods that are effective in controlling worker exposures to tetramethyl lead, depending on the feasibility of implementation, are

• Process enclosure,
• Local exhaust ventilation,
• General dilution ventilation, and
• Personal protective equipment.

The following publications are good sources of information on control methods:

1. ACGIH [1986]. Industrial ventilation--a manual of recommended practice. 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 MONITORING

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, placement of workers in jobs that do not jeopardize their safety or health, 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 monitoring program is intended to supplement, not replace, such measures. To place workers effectively and to detect and control work-related health effects, medical evaluations should be performed (1) before job placement, (2) periodically during the period 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 tetramethyl lead, 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 central nervous and cardiovascular systems.

A preplacement medical evaluation is recommended to assess an individual's suitability for employment at a specific job and to detect and assess medical conditions that may be aggravated or may result in increased risk when a worker is exposed to tetramethyl lead 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 central nervous or cardiovascular systems.

* Periodic medical examinations and biological monitoring

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 tetramethyl lead exposure. The interviews, examinations, and medical screening tests should focus on identifying the adverse effects of tetramethyl lead on the central nervous or cardiovascular systems. Current health status should be compared with the baseline health status of the individual worker or with expected values for a suitable reference population.

Biological monitoring involves sampling and analyzing body tissues or fluids to provide an index of exposure to a toxic substance or metabolite. Exposure to organolead compounds can be determined in the blood or urine of exposed individuals. However, airborne tetramethyl lead concentrations do not correlate well with blood lead levels. Some sources suggest that urinary lead levels are reliable indicators of recent airborne exposure and recommend a biological exposure index of 0.1 mg lead per liter of urine.

* Medical examinations recommended at the time of job transfer or termination

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.

WORKPLACE MONITORING AND MEASUREMENT PROCEDURES

Determination of a worker's exposure to airborne tetramethyl lead is made using a glass fiber prefilter plus a charcoal tube (100/50 mg sections, 20/40 mesh). Samples are collected at a maximum flow rate of 1.0 liter per minute until a maximum air volume of 240 liters is collected. Analysis is conducted by atomic absorption spectroscopy. This method is described in OSHA Method ID 121 of the OSHA Chemical Information Manual [OSHA 1987], and in NIOSH Method No. 2534 [NIOSH 1984].

PERSONAL HYGIENE PROCEDURES

If tetramethyl lead contacts the skin, workers should immediately wash the affected areas with large amounts of soap and water.

Clothing contaminated with tetramethyl lead 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 tetramethyl lead, particularly its potential to cause central nervous system effects.

A worker who handles tetramethyl lead should thoroughly wash hands, forearms, and face with soap and water before eating, using tobacco products, or using toilet facilities.

Workers should not eat, drink, or use tobacco products in areas where tetramethyl lead or a solution containing tetramethyl lead is handled, processed, or stored.

STORAGE

Tetramethyl lead 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. Containers of tetramethyl lead should be protected from physical damage and should be stored separately from oxidizers, chemically active metals, heat, sparks, and open flame. Drums must be equipped with self-closing valves, pressure vacuum bungs, and flame arrestors. Only nonsparking tools may be used to handle tetramethyl lead. To prevent static sparks, containers should be grounded and bonded for transfers. Because containers that formerly contained tetramethyl lead may still hold product residues, they should be handled appropriately.

SPILLS AND LEAKS

In the event of a spill or leak involving tetramethyl lead, 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. Do not touch the spilled material; stop the leak if it is possible to do so without risk.

2. Notify safety personnel.

3. Remove all sources of heat and ignition.

4. Ventilate the area of the spill or leak.

5. Water spray may be used to reduce vapors, but the spray may not prevent ignition in closed spaces.

6. For small dry spills, use a clean shovel and place the material into a clean, dry container; cover and remove the container from the spill area.

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

8. For large liquid spills, build dikes far ahead of the spill to contain the tetramethyl lead for later reclamation or disposal.

EMERGENCY PLANNING, COMMUNITY RIGHT-TO-KNOW, AND HAZARDOUS WASTE MANAGEMENT REQUIREMENTS

The Environmental Protection Agency's (EPA's) regulatory requirements for emergency planning, community right-to-know, and hazardous waste management may vary over time. Users are therefore advised to determine periodically whether new information is available.

* Emergency planning requirements

Employers owning or operating a facility at which there are 100 pounds or more of tetramethyl lead must comply with EPA's emergency planning requirements.

* Reportable quantity requirements (releases of hazardous substances)

A hazardous substance release is defined by EPA as any spilling, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, or disposing into the environment (including the abandonment or discarding of containers) of hazardous substances. In the event of a release that is above the reportable quantity for that chemical, employers are required by the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) to notify the proper Federal, State, and local authorities.

The reportable quantity for tetramethyl lead is 1 pound. If an amount equal to or greater than this quantity is released within a 24-hour period, CERCLA requires employers to notify the National Response Center IMMEDIATELY at (800) 424-8802 (in Washington, D.C. at (202) 426-2675), and 40 CFR Part 355.40 requires employers to notify (1) the State emergency response commission of any State likely to be affected by the release, and (2) the community emergency coordinator of the local emergency planning committee (or relevant local emergency response personnel) and to identify any area likely to be affected by the release.

* Community right-to-know requirements

Employers are not required by Section 313 of the Superfund Amendments and Reauthorization Act (SARA) to submit a Toxic Chemical Release Inventory form (Form R) to EPA reporting the amount of tetramethyl lead 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), EPA has specifically listed many chemical wastes as hazardous. Although tetramethyl lead is not specifically listed as a hazardous waste under RCRA, EPA requires employers to treat any waste as hazardous if it exhibits any of the characteristics discussed above.

Providing more information about the removal and disposal of specific chemicals is beyond the scope of this guideline. EPA, U.S. Department of Transportation, 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 (202) 382-3000 (in Washington, D.C.) 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 tetramethyl lead 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 emergency situations. If the use of respirators is necessary, the only respirators permitted are those 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. Such a program must include respirator selection (see Table 1), an evaluation of the worker's ability to perform the work while wearing a respirator, the regular training of personnel, 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 NIOSH Respirator Decision Logic and the NIOSH Guide to Industrial Respiratory Protection.

Table 1 lists the respiratory protection that NIOSH recommends for workers exposed to tetramethyl lead. The recommended protection may vary over time because of changes in the exposure limit for tetramethyl lead or in respirator certification requirements. Users are therefore advised to determine periodically whether new information is available.

PERSONAL PROTECTIVE EQUIPMENT

Protective clothing should be worn to prevent any possibility of skin contact with tetramethyl lead. Chemical protective clothing should be selected on the basis of available performance data, manufacturers' recommendations, and evaluation of the clothing under actual conditions of use. No reports have been published on the resistance of various protective clothing materials to tetramethyl lead permeation. If permeability data are not readily available, protective clothing manufacturers should be requested to provide information on the best chemical protective clothing for workers to wear when they are exposed to tetramethyl lead.

If tetramethyl lead is dissolved in an organic solvent, the permeation properties of both the solvent and the mixture must be considered when selecting personal protective equipment and clothing.

Safety glasses, goggles, or faceshields should be worn during operations in which tetramethyl lead might contact the eyes (e.g., through splashes of solution). Eyewash fountains and emergency showers should be available within the immediate work area whenever the potential exists for eye or skin contact with tetramethyl lead. Contact lenses should not be worn if the potential exists for tetramethyl lead exposure.

REFERENCES

ACGIH [1986]. Documentation of the threshold limit values and biological exposure indices. 5th edition. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

ACGIH [1991]. TLVs. Threshold limit values and biological exposure indices for 1991-1992. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

[CFR]. Code of Federal regulations. Title 29 (Department of Labor), Parts 1910.134, 1910.1000, and 1910.1200. Washington, DC: U.S. Government Printing Office, Office of the Federal Register.

[CFR]. Code of Federal regulations. Title 40 (Protection of Environment). Washington, DC: U.S. Government Printing Office, Office of the Federal Register.

Gosselin RE, Smith RP, Hodge HC [1984]. Clinical toxicology of commercial products. 5th edition. Baltimore, MD: Williams & Wilkins.

Hathaway GJ, Proctor NH, Hughes JP, and Fischman, ML [1991]. Proctor and Hughes' chemical hazards of the workplace. 3rd edition. New York, NY: Van Nostrand Reinhold.

HSDB [1989]. Tetramethyl lead. Bethesda, MD: The Hazardous Substances Data Bank, National Library of Medicine.

NIOSH [1984]. NIOSH manual of analytical methods. 3rd edition, Volume 1. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health.

NIOSH [1987a]. NIOSH guide to industrial respiratory protection. 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. 87-116.

NIOSH [1987b]. 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 [1990]. 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. 90-117.

OSHA [1987]. Chemical information manual. Washington, DC: U.S. Department of Labor, Occupational Safety and Health Administration.

RTECS [1989]. Tetramethyl lead. Bethesda, MD: Registry of Toxic Effects of Chemical Substances, National Library of Medicine.

BIBLIOGRAPHY

ACGIH [1986]. Documentation of the threshold limit values and biological exposure indices. 5th edition. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

[CFR]. Code of Federal regulations. Title 49 (Department of Transportation). Washington, D.C.: U.S. Government Printing Office, Office of the Federal Register.

DOT [1987]. 1987 Emergency response guidebook, guide 56. Washington, DC: U.S. Department of Transportation, Office of Hazardous Materials Transportation, Research and Special Programs Administration.

Hathaway GJ, Proctor NH, Hughes JP, and Fischman, ML [1991]. Proctor and Hughes' chemical hazards of the workplace. 3rd edition. New York, NY: Van Nostrand Reinhold.

Hawley's condensed chemical dictionary [1987]. Sax NI, Lewis RJ. 11th edition. New York, NY: Van Nostrand Reinhold Company.

Hazardous Substance Fact Sheet [1986]. Tetramethyl lead. Trenton, NJ: New Jersey Department of Health.

HSDB [1989]. Tetramethyl lead. Bethesda, MD: The Hazardous Substances Data Bank, National Library of Medicine.

NFPA [1986]. Fire protection guide on hazardous materials. 9th edition. Quincy, MA: National Fire Protection Association.

Proctor NH, Hughes JP [1978]. Chemical hazards of the workplace. Philadelphia, PA: J.B. Lippincott Company.

RTECS [1989]. Tetramethyl lead. Bethesda, MD: Registry of Toxic Effects of Chemical Substances, National Library of Medicine.

Sax NI, Lewis RJ [1989]. Dangerous properties of industrial materials. 7th edition. New York, NY: Van Nostrand Reinhold Company.

Sittig M [1985]. Handbook of toxic and hazardous chemicals. 2nd edition. Park Ridge, NJ: Noyes Publications.

Condition	Minimum respiratory protection**
Airborne concentration of tetramethyl lead:
0.075 to 0.75 mg/m(3) (10 X PEL)	Any supplied-air respirator equipped with a half mask and operated in a demand (negative-pressure) mode
0.075 to 1.875 mg/m(3) (25 X PEL)	Any supplied-air respirator equipped with a hood or helmet and operated in a continuous-flow mode
0.075 to 3.75 mg/m(3) (50 X PEL)	Any supplied-air respirator equipped with a full facepiece and operated in a demand (negative-pressure) mode, or Any supplied-air respirator equipped with a tight-fitting facepiece and operated in a continuous-flow mode, or Any self-contained respirator equipped with a full facepiece and operated in a demand (negative-pressure) mode
0.075 to 40 mg/m(3) (533.3 X PEL)	Any supplied-air respirator operated in a pressure-demand or other positive-pressure mode
Entry into IDLH(+) or unknown concentrations	Any self-contained respirator equipped with a full facepiece and operated in a pressure-demand or other positive-pressure mode, or Any supplied-air respirator equipped with a full facepiece and operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained breathing apparatus operated in a pressure-demand or other positive-pressure mode
Firefighting	Any self-contained respirator equipped with a full facepiece and operated in a pressure-demand or other positive-pressure mode
Escape	Any air-purifying, full-facepiece respirator equipped with an organic vapor canister, or Any escape-type, self-contained breathing apparatus with a suitable service life (number of minutes required to escape the environment)

* The OSHA PEL is 0.075 mg/m(3) as an 8-hour TWA. No NIOSH REL has been issued.

** Only NIOSH/MSHA-approved equipment should be used. Also note the following:

1. Respirators accepted for use at higher concentrations may be used at lower concentrations; respirators must not, however, be used at concentrations higher than those for which they are approved.

2. Air-purifying respirators are not listed due to the inadequate odor warning properties of tetramethyl lead.

(+) The tetramethyl lead concentration that is immediately dangerous to life or health (IDLH) is 40 mg/m(3) [NIOSH 1990]. Use of chemical protective clothing may be necessary to prevent skin contact.