Document B8aJNgLgjYoag6OBYDNq1eqQE

Target Health Hazards ASBESTOS: AIRBORNE DANGER REPRINTED FROM SAFETY STANDARDS MAY-JUNE 1972 5003:>x*,5 Target Health Hazards Asbestos: Airborne Danger by Xancy L. Xelson Two thousand years ago when, the first use of asbestos was recorded, it was a sacred object, a curiosity of kings and nobles, a magic mineral. The Greeks, who used asbestos for the wicks of their temple lamps, were enthralled when flames did not consume it. but burned unceasingly. Amazed, they called it asbesta, which meant the '`unquenchable,-' the "inextinguishable." ' Xow'that asbestos has been integrated into our industrial world--from fireproof drapery and floor tiles to the corrugated steel used in heavy con struction--the term used by the Greeks has been found to apply to another attribute of this min eral. Xo cure now exists for the diseases caused by inhaling asbestos fibers: once established, these disorders, too. have so far proved to be inextinguishable. In the last few years, asbestos has been recog nized as one of the most hazardous of air con taminants in the workplace. Employees exposed to asbestos include an estimated 100,000 insulation workers. 50.000 workers in manufacturing prod ucts, 60,000 using end products, and uncounted thousands in construction. Labor unions have Mist Xelson 2 the assistant editor of Safett Standards. pushed for stricter standards governing its usa<re, and the Occupational Safety and Health Adminis tration has listed it as one of five target health haz ards in a new program aimed to crack down on health hazards in the workplace. Recent studies, such as those conducted by the Mount Sinai School of Medicine and the Xational Research Council, have produced some disturbing statistics on the mortality rates of workers using asbestos. Dr. Irving J. Selikotf of the Mohnr. Sinai School of Medicine discussed the implications of these studies: "At present, one in e'very five deaths among insulation workers is due to lung cancer, one in ten to cancer of the pleura or peritoneum, one in ten to scarred lungs of asbestosis." Since insulation workers receive relatively light expo sures to asbestos compared to some other occupa tional groups, these results are even more sombre. What disturbs researchers about diseases linked to asbestos is that many cases they are presently en countering result from exposures dating back to the 1930;s. when asbestos was not used as exten sively as it is today. Thirty years ago world pro duction was approximately 50.000 tons annually: today it has skyrocketed to 3 million tons. The effects of exposures occurins in the I970"s probably > i --'V-Vv. - -r*,. ^ , _ -, ... &***&**&' * ^ A >*%jtJkou2>V--if* - - ',.w*` ' j!tT *rC.2' will not ho known until the end of the century: but the high mortality rates of today suggest what may be expected in the future. If working conditions are not signiricantly altered, asbestos exposure can lead to 17,000 deaths from lung cancer. 10.000 deaths from cancer of the pleura and peritoneum, and 10,000 deaths from asbestosis. according to projections by Dr. E. Cuvier Hammond of the American Cancer Society. The first case of asbestosis did not come under medical attention until 1900, '22 years after asbes tos was mined on a large-scale basis. The victim, a British textile worker, had inhaled the asbestos dust stirred up by the carding machine he had operated for 14 years. Ten other men had been his co-workers in the carding room. All died before their thirtieth birthdays. Since the recognition of asbestosis 72 years ago. the disease has been widely studied the world over, from the mines of South Africa to the mills of Quebec. Today experts believe that asbestosis is one of the most debilitating of the pneumoconio ses--lung diseases caused by dust inhalation. Erupting 20 to 30 years after the exposure period, the disease exhibits no warning symptoms to mark its early stages. Many studies have uncovered cases of the disease in which the exposure was relatively light and did not continue over an extended period of time. Although four varieties of asbestos are used commercially, chrvsotile asbestos, mined primarily in Quebec, accounts for 95 percent of world pro duction. Under high magnification, chrysotile fibers resemble fine polished wire or strands of silk. Strong, soft and flexible, they can be woven into fabric. Chrysotile, however, is dangerous medically. When inhaled, the needle-like fibers become trapped in the lower bronchioles of the lungs. Nor mally, protective cells called phagocytes destroy The asbestos worker mixing cement is partially protected by a respirator. The nsbestos fibers in the air. howceer. endanger liis fellow employees, just as his duit-lailen clothes arc u menace to his family. Xcw OAHA standard requires that asbestos materials be mixed in closed containers. 5C030i'i'7 3 t i *i( i i "The effects of exposures occurring in the 1970's probably will not be known until the end of the century; but the high mortality rates of today stiggest what may be expected in the future." such irritants. lint asbestos fibers are indestrnrrr- ble in lung tissue. The phagocytes form a heavy coating around the libers. In time, a dumb-bell shaped structure known as a ferruginous body begins to form. Asbestosis develops when the scar tissue that forms around asbestos libers slowly spreads throughout the lung and pulls it out of shape. The working space for air exchange is reduced, and blood flowing through the lungs is not replenished with a sufficient amount of oxygen. Breathlessness becomes pronounced, and in advanced stages can be disabling. Other symptoms are loss of weight, coughing, weakness, and pain in the chest or be tween the shoulders. The strain on the heart caused by the lack of oxygen may cause heart failure. Recent studies indicate that asbestos also may he a potent carcinogenic, or cancer-producing agent. A major stumbling block to researchers in establishing the connection between asbestosjmd cancer has been the length of time between ex posure to the substance and the appearance of cancer symptoms. But in the last few'years, studies have shown that workers exposed to asbestos die of lurtg cancer at more than five times the expected rate. Although most cancers linked to asbescos de velop in the lower portions of the lungs, where the concentration of libers is heaviest, enneer may also develop in the gastrointestinal tract. The peril of lung cancer from asbestos exposure is increased by smoking. Tests conducted by Selikolf and Hammond have shown that asbestos in sulation workers .who. smoke have 00 times the incidence of lung cancer compared to smokers with no asbestos exposure. Mesothelioma, formerly a rare cancer afflicting only one out of 10.000 people, is now appearing at an unprecedented rate. Researchers are Uniting it to asbestos exposure. However slight. This fatal cancer attacks the pleura (the membrane lining the lung and chest cavity) or the peritoneum (the lining of the abdominal cavity). In his study. Selikotf noted that 10 out of 12-1 deaths of insulation workers were caused by mesothelioma. Workers in many occupations encounter serious asbestos exposures. Among the establishments most likely to have asbestos risks are those manufactur ing asbestos textiles, 'value packings, asbestos Wrong: Spraying asbestos mixtures on steel girders releases vast amounts of asbestos dust into the atmosphere. Asbestos insulators who smoke have 90 times more lung cancer than smokers with no asbestos exposure. 4 5-ram-s '"Since the recognition of asbestosis 72 years ago, the disease has been widely studied the world over, from the mines of South Africa to the mills of Quebec. Today experts believe that asbestosis is one of the most debilitating of the pneumoconioses--lung diseases caused by dust inhalation sheets, brake linings, boiler blankets, building materials and appliance cords. Plasterers who spray an asbestos mix on the steel foundations of buildings have 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 without interrupting construction activities, and the asbestos mixture hardens in eight hours with out cracking or shrinking. Xot only steel buildings, but ships and boats are treated in this manner. Xow 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-'fireproonng mixture, 30 percent of which is chrvsotile asbestos, was sprayed in 1970. Twentyfive percent of the material sprayed does not adhere to the steel, but goes directly into the atmosphere. The plasterers manning the spray guns, as well as the construction workers toiling near-by. inhale excessive amounts of asbestos dur ing this operation--up to 50 million fibers in an eight hour day. But the hazard does not end with contraction. A large amount of asbestos is expected to be set free during' demolition of the 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 heat and its ability to withstand abra sive force, chrvsotile 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 device reduced the hazard in recent tests in England. Insulation workers are the largest single occu pational group to handle asbestos on the job. Their 4*v 5co;j:vi^3 5 ( i < l Wrong: Juicing asbestos materials creates dust in the icork environment. The respirator affords the employee some protection, but the accumulation of dust remains a threat to others on the worksite. Right: .1 saw with a local ventilation system sucks up asbestos (lust into' a container. The OSHA standard specifies that hand or power-operated tools that produce asbestos 'lust must be equipped icith local exhaust ventilation and dust collectors. . exposures, however, are relatively light. In most types of insulation, asbestos is used primarily as a binding agent and makes up only 15 percent of the material. Then. too. insulators working with asbestos on a daily basis are encouraged to take precautions: good housekeeping measures, tools equipped with local ventilation systems, and- res pirators for dusty work are safety precautions stressed by their union. When insulation workers install materials con taining a high percentage of asbestos, they often use a water spray on the cloth while unrolling it or uncovering it. Some insulation workers even cut asbestos on disposable tarpaulins in order to allow the excess material to be discarded without stirring up dust. This eliminates the need to sweep up insulation debris after a job. Usually a dusty process, sweeping is discouraged because it holds a risk for the workers still on the construction site. Bricklayers, carpenters, sheet metal workers and boiler makers also install insulation at various times, but often they fail to take the precautions used by workers who handle asbestos on a daily basis. The licensing of workers who install insula tion, much like the licensing of plumbers and elec tricians. lias been suggested as a safeguard to in sure that asbestos handlers are both informed and equipped to work safely. 6 Asbestos contamination - holds an increasing threat to the general public. Both the dusty manu facturing processes and the spraying of structural steel emit vast amounts of asbestos fibers into the atmosphere, threatening those living near asbestos factories. Unsuspecting passers-by in the vicinity of construction sites or families of workers who return home with dusty clothing are among those exposed to this hazard. The emergency OSHA standard for asuestos, issued on December 7, 1971* lowers the permis sible concentration of asbestos fibers iij cjie work atmosphere from 12 fibers to five fibers greater than five, microns in length per milliliter. This is based on the average exposure during the eighthour work day. Concentrations of asbestos that range from' five fibers per milliliter to 10 are permissible for 15 minutes every hour, but the sum total of such exposure must not exceed five hours in an eight-hour work day. Tire standard also lists engineering controls-- enclosures, vacuum sweeping and local exhaust ventilation. When these measures are not feasible or do not reduce the asbestos concentration to per missible levels, the standard requires that workers be provided with personal protective devices. Pro tective respiratory devices must be worn by workers exposed to the spraying of asbestos, or 5rn;j:)-io to the demolition or pipes, structures or equipment previously sprayed with asbestos. Tiie emergency standard requires that the em ployer check the respiratory devices for proper tit and train employees in their correct use. Peri odic inspections, proper cleaning, repairing and storing of the respiratory devices are responsibili ties of the employer. The standard also specifies that hand or poweroperated tools that produce asbestos dust--saws, scorers, abrasive wheels, and drills--must be equipped with local exhaust ventilation and dust collectors. When asbestos is mixed with other products--such as cement, mortar, grout or plastic--the mixing must be done in closed con tainers. Cleaning up the debris by dry sweeping or blowing it away is prohibited. Any accumula tion of asbestos dust must be removed rapidly by vacuum cleaners. Asbestos waste must be disposed of in scaled containers. The OSHA Standards Aavisorv Committee for Asbestos has recommended an exposure limit of two fibers greater than 3 microns in length per cubic centimeter. This proposal, based on a XIOSH criteria document, would not be erfeetive for two years, in order to allow the installation of the necessary engineering controls. The committee, representing government, labor and industry, also suggested that the future standard include a pro gram of comprehensive medical surveillance re quiring pre-employment medical examinations of applicants, periodic medical evaluations of work ers. and medical records to be kept by employers for the use of OSHA and XIOSH. The research and mortality studies of today have tarnished the reputation of this magic mineral, once the object of fabulous tales. One legend re volves around the tablecloth of Charlemagne, the eighth-century ruler of the Holy Roman Empire. When the cloth woven from asbestos fibers was thrown into the fiames, it was withdrawn not only intact, but whiter and cleaner than before. Charle magne used this piece of "witchcraft" to mystify his guests as well as to intimidate his enemies in order to win psychological battles. The jump from ancient legend to contemporary knowledge about asbestos is a tremendous ad vance--except in one area. Our ability to combat the disasterous effects of asbestos on the human system is still negligible. The mystery surround ing asbestos continues today, but the price is not in lost battles but in lost working lives. Q Wrong: .1 sbestos dust collects with other debris on a construction .site. The cleaning and sweeping process raises clouds of asbestos dust, endangering the employees and the community. Right: The new OSHA. standard requires that asbestos debris be removed in closed containers or plastic bags, 7 A cloud of airborne asbestos descends on construction workers; unwary passers-by and persons living or working near the construction of this multi-story building. Asbestos has recently been recognized as a major health threat both in the workplace and in the community. The practice of spraying asbestos- insulation on steel girders has been halted in some cities. ............... * C. S. GOVERNMENT PRtNTDiC OFFICE: l?T3 O - (27) 5C030152.