Dust masks

Except for siUca and natural abrasives containing free siUca, the abrasive materials used today are classified by NIOSH as nuisance dust materials and have relatively high permissable dust levels (55). The OSHA TWA allowable total dust level for aluminum oxide, siUcon carbide, boron carbide, ceria, and other nuisance dusts is 10 mg/m. SiUca, in contrast, is quite toxic as a respkable dust for cristobaUte [14464-46-1] and tridymite [15468-32-3] the allowable TWA level drops to 0.05 mg/m and the TWA for quartz [14808-60-7] is set at 0.1 mg/m. Any abrasive that contains free siUca in excess of 1% should be treated as a potential health hazard if it is in the form of respkable dust. Dust masks are requked for those exposed to such materials (see Industrial hygene). 

The ACGIH adopted TLV/TWA for 1992—1993 for fluorides as F is TWA 2.5 mg/m, and for cobalt as Co metal dust TWA 0.05 mg/m. Dust masks should be used while handling both the cobalt fluorides and all other cobalt compounds. CoF is shipped as an oxidizer and a corrosive material. 

Potassium biduoride crystals may break down to a fine white powder that is readily airborne. In this form, the salt is quite irritating to the nasal passages, eyes, and skin. Therefore, the hands and eyes should be protected and acid dust masks should be worn while handling, as an acid duoride KHF2 can cause superficial hydroduoric acid-type bums. Areas of skin that have been in contact with potassium biduoride should be washed as soon as possible with mildly alkaline soaps or borax-containing hand cleaners. If there has been contact with the eyes, they should be washed well with water and a physician should be consulted. 

Polyurethanes. These polymers can be considered safe for human use. However, exposure to dust, generated in finishing operations, should be avoided. Ventilation, dust masks, and eye protection are recommended in foam fabrication operations. Polyurethane or polyisocyanurate dust may present an explosion risk under certain conditions. Airborne concentrations of 25—30 g/m are required before an explosion occurs. Inhalation of thermal decomposition products of polyurethanes should be avoided because carbon monoxide and hydrogen cyanide are among the many products present. 

Sodium metaborate hydrates are more alkaline than borax and greater care is required in handling. The metaborate material is harm fill to the eyes and can cause skin irritation. Gloves, goggles, and a simple dust mask should be used when handling sodium metaborate powder. 

Health Hazards Information - Recommended Personal Protective Equipment U.S. Bu. Mines approved toxic dust mask chemical goggles rubber gloves neoprene-coated shoes Symptoms Following Erqrosure Inhalation produces slight toxic effects. Contact with eyes irritates eyes and causes skin rash General Treatment for Exposure INHALATION remove to fresh air. EYES wash with water for 20 min. call a physician. SKIN wash with water Toxicity by Inhalation (ThresholdLimit Value) Data not available Short-Term Exposure Limits Data not available Toxicity by Ingestion Grade 2 oral rat LDjq 820 mg/kg Late Toxicity Data not available Vapor (Gas) Irritant Characteristics Data not available Liquid or Solid Irritant Characteristics Data not available Odor Threshold Data not available. 

Health Hazards Information - Recommended Personal Protective Equipment Dust mask, goggles or face shield, rubber gloves Symptoms Following Exposure Inhalation of dust irritates nose and throat. Ingestion causes irritation of mouth and stomach. Dust irritates eyes and may cause skin irritation on prolonged contact General Treatment for Exposure INHALATION move to fresh air. INGESTION ... 

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