Document xzK3ejqajgeeNd0nJkqXLd5pG

"Since the recognition of asbestosis 72 years ago,,the disease has been tvidcly studied the world over, from the mines oj South Africa to the milts of Quebec. Toduy experts believe that asbestos!s is one of the most debilitating of the pneumoconioses--lung diseases caused by dust inhalation heels, broke linings, boiler blankets, building; materials and appliance cords. Plasterers who spray an asbestos mix on the steel foundations of buildings hare heavy exposures to asbestos. A thermal insulation and fireproofing agent, the asbestos mix prevents the steel from buckling in case of fire. Plasterers can apply it trithout interrupting construction activities, and tho asbestos mixture hardens in eight hours with out cracking or shrinking. Not only steel buildings, but ships and boats arc treated in this manner. Kott that asbestos has been recognized as a major health hazard, the alarming facts about this prac tice are being reviewed. Three million pounds of the fireproofing mixture, 30 percent of which is ehijsotilc asbestos, was sprayed in 1970. Twentyfivo percent of the material sprayed does not adhere to the sted, but goes directly into the atmosphere. Tho plasterers manning the spray guns, as well as the construction workers toiling near-by, inhale excessive amounts of asbestos dur ing tliis operation--up to 50 million fibers in on eight hour day. But the hazard does not end with icontruclion. A large amount of asbestos is expected to be set free during demolition of tho buildings and ships treated in this manner. Asbestos spraying has been banned in some cities, but continues unabated in others. The use of alter nate methods of application--trowelling a wet mixture of asbestos on the foundation or wrapping insulation around the steel in the form of blan kets--is being encouraged to reduce the hazard. Brake mechanics must also cope with significant levels of airborne asbestos. Valuable because of its resistance to beat and its ability to withstand abra sive force, chrysotile asbestos makes up 50 per cent of brake lining material. However, the fric tion breaks asbestos fibers away from the fabric. Many mechanics remove the asbestos fibers that have accumulated around the brake drums and as semblies with a compressed air hose. This produces a cloud of asbestos dust around the mechanic and anyone in his working area. Alternate cleaning methods are needed; for example, a vacuum clean ing deuce reduced the hazard in recent tests in England. Insulation workers are the largest single occu pational group to handle asbestos on the job. Their May-June 1972 Bight: Tmeeting a tcet asbestos mi* on pipetfor insulation purposes effectively reduces the hazards. 5