Respirable dusts

Maleic Anhydride. The ACGIH threshold limit value in air for maleic anhydride is 0.25 ppm and the OSHA permissible exposure level (PEL) is also 0.25 ppm (181). Maleic anhydride is a corrosive irritant to eyes, skin, and mucous membranes. Pulmonary edema (collection of fluid in the lungs) can result from airborne exposure. Skin contact should be avoided by the use of mbber gloves. Dust respirators should be used when maleic anhydride dust is present. Maleic anhydride is combustible when exposed to heat or flame and can react vigorously on contact with oxidizers. The material reacts exothermically with water or steam. Violent decompositions of maleic anhydride can be catalyzed at high temperature by strong bases (sodium hydroxide, potassium hydroxide, calcium hydroxide, alkaU metals, and amines). Precaution should be taken during the manufacture and use of maleic anhydride to minimize the presence of basic materials. 

Health and Safety Factors. Terephthahc acid has a low order of toxicity. Inhalation by rats for 6 h/d, 5 d/wk for 4 wk produced no fatahties at a dust exposure level of 25 mg/m. The mean acute oral toxicity for rats is over 18 g/kg (86), and for mice over 6 g/kg (87). When terephthahc acid was fed as 3% of the diet to rats, urinary calcuh formed in 90 d, some of which led to cancer. High doses of terephthahc acid lead to formation of calcium terephthalate at levels exceeding its solubihty in urine. This insoluble material leads to the calcuh and provides a threshold below which cancer is not observed (88). Normal precautions used in handling industrial chemicals should be observed with terephthahc acid. If ventilation is inadequate, a toxic-dust respirator should be used to avoid prolonged exposure. 

Thorium is potentially hazardous. Einely divided thorium metal and hydrides can be explosive or inflammatory hazards with respect to oxygen and halogens. Einely divided Th02 and other inorganic salts also present an inhalation and irritation hazard. The use of standard precautions, skin covering, and a conventional dust respirator should be sufficient for handling thorium materials. 

Because routine inhalation of dust of any kind should be avoided, reduction of exposure to poly(vinyl chloride) dust may be accompHshed through the utilization of care when dumping bags, sweeping, mixing, or performing other tasks that can create dust. The use of an approved dust respirator is recommended where adequate ventilation may be unavailable. 

Silane, see Silicon tetrahydride Silica, Amorphous Total inhalable dust Respirable dust Precipitated... 

Withdrawn) 1970 Positive pressure, powered dust respirators. Withdrawn, superseded by BS EN 136 1990, BS EN 143 1991 and BS EN 147 Clothes lockers. Superseded BS 4680 1971... 

Physical and Chemical Properties - Physical State at 15 X and 1 atm. Solid Molecular Weight 168. Boiling Poira at 1 atm. 556,291,564 Freezing Point 194,90,363 Critical Temperature Not pertinent Critical Pressure Not pertinent Specific Gravity 1.58 at 18°C (solid) Vapor (Gas) Density Not pertinent Ratio of Specific Heats of Vapor (Gas) Not pertinent Latent Heat of Vaporization Not pertinent Heat of Combustion -7,378, -4,099, -171.5 Heat of Decomposition Not pertinent. Health Hazards Information - Recommended Personal Protective Equipment Dust respirator rubber... 

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