Document b5bwEMj4xgj3Zq1Z1n6EknK0g

gnaugtrial Hygiene Digest February, 1956 ventilation, firat because carbon dioxide and moat toxic materials are heavier than air, aod aecood, becauae aatural diffusion la very alow. The principal effect of carbon dioxide la asphyxiation, and many other materiela are aaeathetic. A table gives rapidly fatal con* eentrattona of carbon tetrachloride, trichloroethylene, and benzene and the denaity of anch mixturea relative to air, all of which are definitely ever one. Anesthetic effects may be produced by concentrations as low as one-third of those which are rapidly fatal. The follow, 'lug precautions are recommended: (1) each worker who enters a pit should wear a harness with a rope or cable held by another worker outside the enclosure, aod a third worker should be available for assistance; (Z) no enclosed or partly enclosed space should be entered until its contents of volatile or partly volatile material are removed; the air should be tested (or oxygen content; (3) clean, fresh air should be supplied to the tank after contaminants are re moved; (4) If the contaminants cannot be completely removed, the worker who la to eater must be provided with a positive source of respirable air or oxygen (an "all purpose1' gas mask is useless); (5) if operations are to be performed la such spaces, exhaust ventilation balanced with an equal volume of supplied uacontaminated air must be used; and (6) when skin absorption of contaminants is possible, protective clothing should be provided. These precautions art described la.greater detail. 303 Polo-Top Resuscitation. Data Sheet 0-376, National Safety Council. Natl. Safety News 72, 33-39 (Dec. 1935), Pole-top resuscitation is often necessary immediately after an electric shock, without wetting until the rescuer and victim are in the moat comfortable and ideal positions. The standard and modified methods are deserioed. The procedure will be determined largely by the individual company policy and the training, confidence, and resourcefulness of the rescuer. Detailed instructions are given for the rescuer and assistants, including precau tions for the' safety of the rescuers, methods of placing the victim in position, lowering the victim to the ground, after-shock precautions, and training of line crews. 304 The Suppression of Methane-Air Ignitions by Fine Powders. J. E. Dolau and P. 2. Dempster. Appl Chem. 4, 5l6-6'l7 (SoptT'VKWJl The effect of the particle size of some inorganic materials ou their efficiency as ignition suppressors has been studied. It has been found that there is a direct relationship between this efficiency and the surface area of the powder exposed to the advancing flame. Flame inhibitors have bssn placed in an order of efficiency ou this basis. The alkali halides have been shown to have an efficiency which cannot be fully accounted to; by the thermal characteristics of the powders, and an explanation is suggested. -- Editor11 summary 305 Thirty-Second Annual Report ou Safety in Mines Research 1933. Great Britain, Ministry of Fuoi and Power, Safety in Mines Research Establishment, Porcobello St., Sheffield, England. A. H. A. Wynn, Director. 83 pp. (1954). 65 cents. This report describes a wide variety of researches concerned with safety and health In mines. Among the subjects are: development of safer methods of blasting; meas urement of depoaitiou of coal dust; studies of the use of stone dust (or prevention of explo sions; studies of breathing apparatus; research ou dust sampling problems; st&dy of dust produced by rotary drilling; studies of the hazards of ksoiiulte dust; and studies of the amorphous layer ou silica dust. Much of this work has been presented la papers which considered seme of these subjects in detail. -- Cond. from Bull. Hyg. 11 206 1386 37.