Document oe6Qr9BpQvKMgejzv048m1EK3

can withstand concentrations approaching 15 mg/ni1 before complaining of ocular or nasal irritation An adequate ventilation system should be employed to maintain air borne dust below the TLV If circumstances arise which do not permit adequate control at the source, then approved respiratory pro tective devices should be used to prevent in halation of bispheno! A dust Clothing must be frequently laundered to prevent continu ous skin contact, personal cleanliness is es sential to avoid skin difficulties Bone acid has been used for many years as a mild disinfectant and a soothing and slightly astringent wet dressing or ointment with little attention to its toxicity Poisoning is not usually an industnal prob lem since the human system processes and eliminates fairly large quantities of boric acid without trouble, but it may result from misguided first-aid attempts Boric acid is not readily absorbed through the intact skin, but may be absorbed through large areas of skin which are seriously dam aged, as in bums or areas of superficial lacera tions If such areas are dusted with boric acid or covered with strong boric acid oint ment, toxic amounts may be absorbed Boron hydrides are a senes of compounds analogous to the hydrocarbons, and include diborane, pentaborane, and decaborane, which have found use as high-energy fuels Diborane is pnmanly a lung-injuring matenal and produces lung changes in rats in one to four weeks of daily exposure at about 2 ppm The compound has an odor, but it is not detectable at a low enough concentration to act as a warning of the possibility of chronic poisoning Pentaborane, unlike diborane, principally affects the central nervous system In lab oratory animals it produces first a temporary excitement and hypersensitivity which may lead to convlusions, and then a profound de pression Decaborane is similar in its action on the system to pentaborane It can be cumula tively absorbed over a short series of expo sures and the total dose, although less than a single lethal dose, may still cause death In practice it is probably more dangerous to handle than pentaborane, since, in addition to being toxic by inhalation, decaborane is rapidly absorbed through the intact skin Attempts to treat or counteract its toxicity have been unsuccessful Boron hydrides should be handled only in a closed system m a well-hooded and venti lated area Self-contained or supplied air respiratory protection should be provided if the system must be opened (filter-type res pirators are not effective) For the handling of decaborane, impervious clothing should also be used to prevent skin contact See Industnal Data Sheet 508 Brass, chiefly an alloy of copper and zinc, may also contain lead Melting of brass may produce copius quantities of zinc oxide fume which, if inhaled, may give nse to the signs and symptoms of metal fume fever (See listings for Copper, Lead, and Zinc in this chapter) Bromine is a dark red, low-boiling liquid which produces large quantities of extremely imtant, nonflammable vapor at room temper ature or above Its physiological effects are about the same as those of chlorine --irrita tion of all mucous membranes and the lungs and spasm of the glottis when inhaled in fairly large concentration A bromine concentra tion of 40 to 60 ppm is reported to be danger ous on short exposure The imtant action of bromine is not re lated to the bromide intoxication seen fiom time to time from continued overdoses of bromides as sedatives In bromide intoxica tion, the most notable effects are on the cen tral nervous system and are seen as slurring of speech, somnolence, difficulty in walking, and various psychic disturbances, depending on the personality of the individual involved See Industnal Data Sheet 313 and Hy gienic Guide Bromochloromethane (methylene chlorobromide) Knowledge of effects in humans is limited at present Anesthesia is the pnmary hazard from single exposure to high concentrations and organic (liver) injury is likely only if severe anesthetic effects are apparent Repeated exposure to moderately excessive concentrations is likely to result in slight liver injury The matenal has a low oral toxicity and does not present a problem from skin absorption Bromochloromethane is slightly irritating to the eyes and has a de fatting effect on the skin Fire extinguishers containing bromochlor- 1333