FIRES AND EXPLOSIONS CAUSED BY CARELESS USE OF SOLVENTS
New York State Division of Industrial Hygiene And Safety Standards Makes Helpful Suggestions
TWO employees in a rubber products plant, where soles and heels are molded for shoes, bent to their task of cleaning solidified deposits of once hot rubber from the plant floor. They worked separately, one carrying a gallon can of naphtha and a bunch of rags, the other, a keen bladed scraping knife. They didn’t smoke because they knew that a match or a cigaret ash could ignite naphtha vapors. Fnally the one with the rag rose up in disgust from his work where old rubber stains resisted his rubbing efforts. The second man moved over and attacked the stubborn deposit with his knife. The flash fire that resulted from a spark flying off the knife blade badly burned both men —damaged stock and equipment.
A few weeks later the plant installed the precautionary measures previously recommended to them by the Division of Industrial Hygiene, it was the old story of the locked, but empty stable. There are other versions of the story, all involving indiscriminate use of flammable materials, particularly solvents. Brief sketches of these occurrences, all from the files of the Division of Industrial Hygiene and Safety Standards, are as follows:
- Explosion and fire occurred when naphtha fumes from a heated tank became ignited by nearby open flames or spark from electric switch. One died.
- Explosion and fire occurred when a combustible dyestuff was being unloaded from a drier where a portable electric lamp served as illumination. Two persons killed.
- A can of acetone burst into flames when a workman attempted to pry it open with a hammer and screwdriver of sparking metal. Several large drums of alcohol spread the flames. Considerable property loss.
- Plant destroyed by fire when a workman broke the bulb of connected portable lamp while he was washing a paint spray gun with flammable solvent. Personal injury and heavy property loss.
- Employees were cleaning machinery with gasoline when one leaned against a switch controlling a lathe. Sparks from switch ignited gasoline vapors. Considerable property loss.
- Fire occurred in a spray painting booth when workmen dropped a filter frame containing flammable lacquer residues against steel grating on concrete floor. One death, one injury.
- Welding an “empty” gasoline tank on a tank truck, a worker was killed when the flammable vapor in the tank became ignited and the tank exploded.
- Dust from magnesium grinders being collected by dry, unsafe type of dust collector took fire and exploded when a spark fronj a swing grindei working other castings entered the exhaust duct. Two persons killed.
- When welding work was being done in the ducts of an acetone recovery unit, explosion occurred, wrecking a textile plant. Seventy-three employees injured and $500,000 loss.
Cost in Money, Lives
Although each of the above case histories diners in exact cause there are figures available which give an overall picture of this problem of flammability hazards arising from the presence of flammable dusts, liquids, vapors, or gases in industrial processes. The federal government reports of dust explosions alone in the United States in the years from 1923 to 1942 show that these explosions caused the death of 308 persons, injury to 680 others and property damage of over 34 million dollars. Moreover fires and explosions from flammable gases, vapors, and liquids have caused even greater injury for a recent three-year period. During this period, flammable solvents in industrial and home use were responsible for more than 60,000 fires in the country; and these fi.res killed about 3,000 persons, seriously injured many more thousands, and destroyed property valued at nearly 15 million dollars.
The Division feels that most, if not all of these fires could have been avoided had personnel involved been properly awaye of the great danger lurking in the use of these solvents. In general, whenever flammable vapors or dusts are present the following elementary precautions, underlying fire and explosion prevention, should be taken:
- Eliminate all fires, flames, and sources of sparks or high temperatures and prohibit smoking. In areas where flammable vapors are present only nonspa, king bronze tools should be used and in extyeme cases, tobacco and matches should be removed from workers before they enter the area and conductive rubber shoes with no metal in the soles should be worn.
- Install all electrical equipment in accordance with the requirements of the National Electyical Code for hazardous locations. Ordinary portable electric lamps should never be used.
- Eliminate static by electrically grounding all equipment for handling flammable solvents, including funnels and portable containers when the latter are being filled or emptied. Gyinders and mixers for flammable dusts should be effectively grounded for static removal.
- Provide ample ventilation to keep the concentration of flammable vapors and dusts far below the lower explosive limit.
- Provide adequate fire-extinguishing equipment of the proper types and train all workers in their use.
- Make sure that each employee is aware of the hazards of his work and knows what must be done to prevent fire.—N. Y. State Labor Dept. Bulletin.