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This guideline summarizes pertinent information about tellurium hexafluoride (measured as tellurium) 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 Recommendations may be superseded by new developments; readers are therefore advised to regard these recommendations as general guidelines and to determine periodically whether new information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 TeF(6) * Structure (For Structure, see paper copy) * Synonym Tellurium fluoride. * Identifiers
Tellurium hexafluoride is a colorless, noncombustible gas with a repulsive odor. CHEMICAL AND PHYSICAL PROPERTIES * Physical data
There is no National Fire Protection Association fire hazard rating for tellurium hexafluoride; this substance is not combustible.
* Warning properties No information is available on the odor threshold for tellurium hexafluoride. * Eye irritation properties No information is available on the specific concentration of tellurium hexafluoride at which eye irritation begins; however, this substance is known to be a severe eye irritant. EXPOSURE LIMITS The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for tellurium hexafluoride (measured as tellurium) is 0.02 part per million (ppm) parts of air (0.2 milligram per cubic meter (mg/m3)) as an 8-hour time-weighted average (TWA) concentration [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 tellurium hexafluoride; however, NIOSH concurs with the PEL established for this substance by OSHA [NIOSH 1988]. The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned tellurium hexafluoride (measured as tellurium) a threshold limit value (TLV) of 0.02 ppm as a TWA for a normal 8-hour workday and a 40-hour workweek [ACGIH 1992, p. 34]. The ACGIH limit is based on the risk of respiratory effects and on analogy with the effects of ozone [ACGIH 1986, p. 556]. HEALTH HAZARD INFORMATION * Routes of exposure Exposure to tellurium hexafluoride can occur via inhalation and eye or skin contact. * Summary of toxicology
* 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:
The following operations may generate or involve tellurium hexafluoride and lead to worker exposures to this substance:
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 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. * Pre-placement medical evaluation Before a worker is placed in a job with a potential for exposure to tellurium hexafluoride, 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 respiratory system. Medical monitoring for respiratory disease should be conducted using the principles and methods recommended by NIOSH and the American Thoracic Society. A pre-placement medical evaluation is recommended to assess medical conditions that may be aggravated or may result in increased risk when a worker is exposed to tellurium hexafluoride 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 respiratory system. * 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 tellurium hexafluoride exposure. The interviews, examinations, and medical screening tests should focus on identifying the adverse effects of tellurium hexafluoride on the 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. Biological monitoring involves sampling and analyzing body tissues or fluids to provide an index of exposure to a toxic substance or metabolite. Although tellurium compounds can be detected in the exhaled breath, sweat, urine, and feces of exposed individuals, levels in biological specimens do not correlate well with airborne concentrations. Therefore, no biological monitoring test acceptable for routine use has yet been developed for tellurium hexafluoride. * 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 tellurium hexafluoride (measured as tellurium) is made using a mixed cellulose ester filter (MCEF) in series with a charcoal tube (100/50 mg sections, 20/40 mesh). Samples are collected at a maximum flow rate of 1 liter per minute until a maximum air volume of 400 liters is collected. The sample is then treated with 0.1N sodium hydroxide to extract the tellurium hexafluoride. Analysis is conducted by atomic absorption spectroscopy. This method is described in NIOSH Method No. S187 [NIOSH 1977].
PERSONAL HYGIENE PROCEDURES If tellurium hexafluoride gas contacts the skin, workers should wash the affected areas with soap and water. Clothing contaminated with tellurium hexafluoride should be removed immediately, and provisions should be made for the safe removal of the chemical from the clothing. A worker who handles tellurium hexafluoride should thoroughly wash hands, forearms, and face with soap and water before eating, using tobacco products, using toilet facilities, or applying cosmetics. Workers should not eat, drink, use tobacco products, or apply cosmetics in areas where tellurium hexafluoride is generated, handled, processed, or stored. STORAGE Tellurium hexafluoride 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 tellurium hexafluoride should be protected from physical damage and should be stored separately from heat. LEAKS In the event of a leak involving tellurium hexafluoride, 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 leak:
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 tellurium hexafluoride 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 tellurium hexafluoride 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 tellurium hexafluoride 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 tellurium hexafluoride 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 tellurium hexafluoride 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 tellurium hexafluoride. The recommended protection may vary over time because of changes in the exposure limit for tellurium hexafluoride 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 skin contact with tellurium hexafluoride. 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 tellurium hexafluoride 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 tellurium hexafluoride. Safety glasses, goggles, or faceshields should be worn during operations in which tellurium hexafluoride might contact the eyes. Eyewash fountains and emergency showers should be available within the immediate work area whenever the potential exists for eye or skin contact with tellurium hexafluoride. Contact lenses should not be worn if the potential exists for tellurium hexafluoride exposure.
ACGIH [1986]. Documentation of the threshold limit values and biological exposure indices. 5th edition. Cincinnati, OH: American Conference of Governmental Industrial Hygienists. ACGIH [1992]. Threshold limit values for chemical substances and physical agents and biological exposure indices for 1992-1993. Cincinnati, OH: American Conference of Governmental Industrial Hygienists. Clayton G, Clayton F [1981-1982]. Patty's industrial hygiene and toxicology. 3rd revised edition. New York, NY: John Wiley & Sons. [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. 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. NIOSH [1977]. NIOSH manual of analytical methods. 2nd edition. Cincinnati, OH: U.S. Department of Health, Education, and Welfare, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health. NIOSH [1988]. Testimony of the National Institute for Occupational Safety and Health on the Occupational Safety and Health Administration's proposed rule: 29 CFR 1910, Docket No. H-020, August 2, 1988. NIOSH policy 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. RTECS [1993]. Tellurium hexafluoride. Bethesda, MD: Registry of Toxic Effects of Chemical Substances, National Library of Medicine.
ACGIH [1986]. Documentation of the threshold limit values and biological exposure indices. 5th edition. Cincinnati, OH: American Conference of Governmental Industrial Hygienists. Clayton G, Clayton F [1981-1982]. Patty's industrial hygiene and toxicology. 3rd revised edition. New York, NY: John Wiley & Sons. [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 15. Washington, DC: U.S. Department of Transportation, Office of Hazardous Materials Transportation, Research and Special Programs Administration. HSDB [1992]. Tellurium hexafluoride. Bethesda, MD: The Hazardous Substances Data Bank, National Library of Medicine. Lide DR [1992-1993]. CRC handbook of chemistry and physics. 73rd edition. Boca Raton, FL: CRC Press, Inc. Material Safety Data Sheet No. 250 [1988]. Schenectady, NY: Genium Publishing Corporation. 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. 85-114. Proctor NH, Hughes JP [1978]. Chemical hazards of the workplace. Philadelphia, PA: J.B. Lippincott Company. RTECS [1993]. Tellurium hexafluoride. Bethesda, MD: Registry of Toxic Effects of Chemical Substances, National Library of Medicine. Sittig M [1991]. Handbook of toxic and hazardous chemicals. 3rd edition. Park Ridge, NJ: Noyes Publications.
Table 1. NIOSH recommended respiratory protection for workers exposed to tellurium hexafluoride*
* The OSHA PEL is 0.02 ppm (0.2 mg/m3) as an 8-hour TWA. No NIOSH REL has been issued. ** Only NIOSH/MSHA-approved equipment should be used. Also note the following:
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