SAFETY Aluminum Should Be Recognized As α Hazardous M a t e r i a l T h e "aluminum explosion" described recently in C&EN (Nov. 23, 1953, page 4 9 4 6 ) has caused some readers to fear w e do not recognize aluminum's poten tial hazards. Aluminum is flammable when ignited and explosive when finely divided (following zirconium, magne sium, and titanium in scale of explo sive dusts ). Less appreciated is the violent reac tion between aluminum (and also mag nesium) with chlorinated hydrocar bons under some conditions. Two men were killed in England in 1950 while experimenting with carbon tetrachloride 1 for making aluminum pastes. The ball mill exploded and ignited the building. A third man was rescued from the fire by heroic action. A previously unre ported experiment of the Director of Armaments Research was cited in which a mixture of 3Qr/r aluminum and 70% carbon tetrachloride was placed in a steel tube. Tube was ignited by detonation under 300-lb. weights. Effect of aluminum and its alloys on the eye was reviewed. Research in pre vention of silicosis b y inhalation of finely divided aluminum dust is still not conclusive. Exposure to aluminum dust is probably n o t harmful. Molten aluminum can be handled safely if precautions are observed. Re duction mixture of barium sulfate with powdered aluminum exploded violently. Sodium peroxide reacted with alu-
Alpha Chi Sigma Poster Number 12 in Alpha Chi Sigma's labora tory safety poster series is available from the group at 5503 East Washington St., Indianapolis 19, Ind., at 10 cents
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minum powder (in presence of alumi num chloride), built up pressure to 1800 lb./sq. in. in 41 days, and residue re acted spontaneously with air. Bromine vapor reacts with warm alu minum foil with brilliant incandescence. With liquid bromine, aluminum reacts energetically at 15° C. Fragments of aluminum on liquid bromine become incandescent. Powdered aluminum mixed with sil ver chloride, once reaction starts, pro ceeds with explosive violence unless ex cess of aluminum is present. Two ox/hydrogen gas explosions oc curred in a dip containing glues of vegetable origin, water, potassium ni trate, barium nitrate, sulfur, and alu minum dust. Nitrate may have reduced to nitrite, rendering mixture weakly alkaline, which then reacted with alu minum to evolve hydrogen. Four work ers received fatal burns. Third Q u a r t e r Injury Rates A r e Low, Upsetting Usual P a t t e r n The all-manufacturing injury-fre quency rate dropped to a new low in third quarter of 1953, according to U. S. Department of Labor's Bureau of Labor Statistics. Average of 13.9 dis abling work injuries per million manhours was lr/c below the previous third quarter low of 14.9 recorded in 1952. It was also lrA below the average for second quarter of 1953—first time in nine years it has been lower than in the second quarter of the same year. As a result, cumulative frequency rate for first nine months of 1953 reached a new low—14.0, or 5r/r below corre sponding rate for 1952. Among industries recording very low rates are synthetic fibers, synthetic rub ber, and explosives. •
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^ S m i t h - D o u g l a s s Co. (Norfolk, Va.) has published an employee safety book let which it says is "the first safety booklet of any kind ever published ex clusively for the use of a fertilizer manufacturing company." The 18-page booklet includes many cartoons and stresses good housekeeping, proper care of machinery and machine shops, and proper fire protection. ^ Los Angeles City Building Code may
b e amended so it will be more realistic and practical in its treatment of hazard ous materials. A public hearing on the proposed ordnance will be held in city hall on May 13. ^ Dow's T e x a s division awards cer tificates for working 100,000 man-hours without a lost-time injury. Among 258
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those receiving awards are: Magnesium 1, Magnesium 2, and Magnesium 3. ^ A fire safety device which continu ously indicates whether carbon dioxide fire extinguishers are full or empty and also saves considerable maintenance ex pense has b e e n introduced by Mel-Rod Mfg. Known as Silent Sentry, device serves as a mounting bracket and con tinuous weigher for all standard ex tinguishers . A collar, included with the unit, fastens around the neck of the bot tle permanently and permits instant use of t h e extinguisher. S 1 ^>A line o f air-pressurized Aifco dry
chemical fire extinguishers stops fires faster, says Arrierican-LaFrance-Foamite. Extinguisher operates by pulling a pin a n d squeezing a lever. Its efficiency is s a i d to b e aided by a discharge noz zle which fans dry chemical outward and downward in wide pattern and with great density. Five-, 10-, 20-, and 30-lb. sizes are available. S 2 ^ Safety spectacles with methacrylate lenses give almost complete protection from eye injuries but weigh only about 1 oz., according to Watchemoket Opti cal. Over-eyes protection from glare and flying particles is provided by an extension of the frame, shaped to fit snugly against the forehead. Called Visor-Tuc Eye Savers, they are avail able i n clear and three shades of green. S 3 ^ Heavy duty w o r k clothing of 2 5 %
Dynel and 75 °/o reprocessed wool have a life expectancy 4 0 % higher than allwool garments of same weight, accord ing t o Chem-Wear. Garments (shirts and -trousers) are said to have good resistance to chemicals and intense heat. S 4 y Lightweight g a r m e n t s for high t e m p e r a t u r e w o r k have been de veloped b y Fyrepel Products. Made of coated or aluminized glass with a Fiberglas insulation liner, they include hoods, helmets, short and long coats, trousers, boots, aprons, and hard pads. S 5
^ Discharge valve said to eliminate valve failure in dry chemical fire ex tinguishers is included in Stop-Fire's Redi-Flo Mark II extinguisher. Called Spheral Valve, it is of spherical design, thus assuring accurate, secure valve seating at all times. Extinguisher can hold its operating pressure, even though it h a s been partially discharged re peatedly, according to Stop-Fire. S 6 For further Information on any keyed item mentioned here, see coupon on page 266 AND
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