Permissable exposure limit

POLYETTiERS - TETRAHYDROFURAN AND OXETANE POLYTffiRS] (Vol 19) PEL. See Permissible exposure limit. 

Material Safety Data Sheets (MSDS) issued by suppHers of acetone ate requited to be revised within 90 days to include new permissible exposure limits (PEL). Current OSHA PEL (54) and ACGIH threshold limit values (TLV) (55) ate the same, 750 ppm TWA and 1000 ppm STEL. Eot comparison, the ACGIH TWA values for the common mbbing alcohols are ethyl, 1000, and isopropyl, 400 ppm. A report on human experience (56) concluded that exposure to 1000 ppm for an 8-h day produced no effects other than slight, transient irritation of the eyes, nose, and throat. 

Air Contaminants—Permissible Exposure Limit," Title 29 Code of Federal Regulations Part CFR 1910.1000, OSHA, 1989, p. 3112. 

The OSHA permissible exposure limit (11) and the American Conference of Governmental Industrial Hygienists (ACGIH) estabHshed threshold limit value (TLV) (12) for fluorides is 2.5 mg of fluoride per cubic meter of air. This is the TLV—TWA concentration for a normal 8-h work day and a 40-h work week. 

Stannous fluoride is used in dentifrices and dental preparations. The OSHA permissible exposure limit (44) and ACGIH (45) estabUshed TLV for fluoride is 2.5 mg/m of air. 

Handling and Toxicity. Tungsten hexafluoride is irritating and corrosive to the upper and lower airways, eyes, and skin. It is extremely corrosive to the skin, producing bums typical of hydrofluoric acid. The OSHA permissible exposure limits is set as a time-weighted average of 2.5 mg/kg or 0.2 ppm (22). 

Colorado has a monthly mean. The OSHA permissible exposure limit (PEL) for lead is 50 at an action level (local authorities must investigate) of... 

However, if air sampling estabHshes that the lead exposure concentration is excessive, engineering controls (such as improved ventilation), adrninistrative controls (such as job rotation), and work practices (such as improved personal hygiene of workers) have to be appHed to comply with the permissible exposure limit (PEL) of the OSHA standard. 

Safety. Magnesium oxide (fume) has a permissible exposure limit (PEL) (134) (8 hours, TWA), of 10 mg/m total dust and 5 mg/m respirable fraction. Tumorigenic data (intravenous in hamsters) show a TD q of 480 mg/kg after 30 weeks of intermittent dosing (135), and toxicity effects data show a TC q of 400 mg/m for inhalation in humans (136). Magnesium oxide is compatible with most chemicals exceptions are strong acids, bromine pentafluoride, chlorine trifluoride, interhalogens, strong oxidizers, and phosphorous pentachloride. 

Value is a PEL C, ie, permissible exposure limit ceiling exposure limit. 

PPS dust should be treated as a nuisance particulate. The OSHA permissible exposure limit for respirable dust is 5 mg/m for dust containing no asbestos and less than 1% siUca. The principal decomposition products released during mol ding of PPS and their permissible exposure limits are given in Table 10. Sulfur dioxide and carbonyl sulfide are the most significant off-gases for production of mucous membrane irritation. 

Use of isopropyl alcohol in industrial appHcations does not present a health hazard. The alcohol produces anesthetic effects in high vapor concentration. Consequently, the OSHA permissible exposure limit (PEL) and the ACGIH threshold limit value (TLV) have been estabUshed at 400 ppm (0.098 mg/L) for an 8-h exposure (TWA) (138). This level causes a mild irritation of the eyes, nose, and throat (139). However, the TLV level does not produce symptoms of anesthesia (140). The OSHA and ACGIH short-term exposure limits (STELs) are 500 ppm. The odor threshold for isopropyl alcohol ranges from 3 to 200 ppm, which is the minimum concentration having identifiable odor (141). 

Occupational Safety and Health. OSHA has set no specific limits for sodium and potassium sibcates (88). A pmdent industrial exposure standard could range from the permissible exposure limit (PEL) for inert or nuisance particulates to the PEL for sodium hydroxide, depending on the rate of dissolution and the concentration of airborne material. Material safety data sheets issued by siUcate producers should be consulted for specific handling precautions, recommended personal protective equipment, and other important safety information. 

Health and Safety Factors. Sulfur monochloride is highly toxic and irritating by inhalation, and is corrosive to skin and eyes (156). The OSHA permissible exposure limit is 1 ppm (6 mg/m ). Pulmonary edema may result from inhalation. Because its vapor cannot be tolerated even at low concentrations, its presence serves as a warning factor. Sulfur monochloride is not highly flammable, having flash poiats of 118°C (closed-cup) and 130°C (open-cup) and an auto-ignition temperature of 234°C. 

The threshold limit value (TLV) set by the American Conference of Industrial Hygienists (ACGIH) for teUurium and its compounds is 0.1 mg/m which is about ten times the amount which has been known to produce the adverse garUc odor (45,50). The ACGIH TLV for teUurium hexafluoride is 0.1 mg/m or 0.02 ppm of air. Likewise, the U.S. Occupational Safety and Health Administration (OSHA) has estabUshed its permissible exposure limit (PEL) for teUurium and its compounds at 0.1 mg/m the PEL for teUurium hexafluoride is 0.2 mg/m or 0.02 ppm of air (50). 

The current OSHA TLV standard for exposure to all organotin compounds is 0.1 mg of organotin compounds (as tin)/m air averaged over an 8-h work shift (192). NIOSH has recommended a permissible exposure limit of 0.1 mg/m of tin averaged over a work shift of up to 10 h/d, 40 h/wk Reference 193 should be consulted for more detailed information. Additional information on the health effects of organotin compounds is given in Reference 48. 

Permissible exposure limits estabhshed by the U.S. Department of Health and Human Services and the U.S. Department of Labor are summarized below, with the mote restrictive levels proposed by NIOSH (47). 

Permissible Exposure Limits in Air. Occupational exposure to insoluble tungsten needs to be controlled so that employees are not exposed to insoluble tungsten at a concentration greater than 5 mg tungsten/m air, determined as a TWA concentration for up to a 10-h workshift in a 40-h workweek. An STEL value of 10 mg/m has been set by ACGIH in 1983. 

The handling of arsenic in the workplace should be in compliance with the Occupational Safety and Health Administration (OSHA) regulations the maximum permissible exposure limit for arsenic in the workplace is 10 p-g/m of air as deterrnined as an average over an 8-h period (33). 

In 1971 the OSHA standard for benzene (20 CFR, Part 1910.0000) adopted a permissible exposure limit (PEL) of 10 ppm benzene measured as an 8-h TWA. In October of 1976 NIOSH updated its earlier criteria document on benzene and recommended that OSHA lower the benzene exposure standard from 10 to 1 ppm. This proposed implementation was blocked by the United States Supreme Court iu 1980 on the basis of iusufficient evidence linking benzene to cancer deaths. By the mid-1980s convincing evidence of the carciuogenicity of benzene appeared through animal studies which justified reconsideration of the 1 ppm PEL (130). 

Effective Dec. 10, 1987, the existing standard for benzene was amended under OSHA (29 CER, Part 1910.1028). The revised standard reduced the permissible exposure limit from 10 ppm (32 mg/m ) to 1 ppm (3.2 mg/m ) iu an 8-h TWA. The short term exposure limit (STEL) of 5 ppm was set over a 15 min period. The standard also established action level requirements for exposure over 0.5 ppm. 

For worker exposure to trichloroethylene vapor, OSHA set a maximum eight-hour time-weighted average (TWA) concentration of 100 ppm. This severely restricted certain appHcations, and many organizations converted to other chlorinated solvents. As a result, U.S. production of trichloroethylene declined about 70% from a peak in 1970 (Table 2). In 1989, OSHA lowered the permissible exposure limit (PEL) from 100 ppm eight-hour TWA to 50 ppm eight-hour TWA (33). This added further pressure for some users to consider changing to alternative solvents. 

Exposure occurs almost exclusively by vapor inhalation, which is followed by rapid absorption into the bloodstream. At concentrations of 150—186 ppm, 51—70% of the trichloroethylene inhaled is absorbed. MetaboHc breakdown occurs by oxidation to chloral hydrate [302-17-OJ, followed by reduction to trichloroethanol [115-20-8] part of which is further oxidized to trichloroacetic acid [76-03-9] (35—37). Absorbed trichloroethylene that is not metabolized is eventually eliminated through the lungs (38). The OSHA permissible exposure limit (PEL) eight-hour TWA concentration has been set at 50 ppm for eight-hour exposure (33). 

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