Document 6BDao2pYwvER8rKVr8Qvk2qjE

fi 0%** * ^ ^ * \ * "t * ' a / TO*THE DISCOVERY COMPANY )N CARBIDE CORPORATION - MINING AND METALS DIVISION 270 PARK AVENUE, NEW YORK NEW YORK 10017 ^PLEASE REPLY TO: "CALIDRIA. ASBESTOS" . - P. 0. BOX 579 - NIAGARA FALLS, N. Y. 14302 p&P-)lU/V$ 1 3 // TOXICOLOGY REPORT -- ---------------------------------------------------------------------------------- '` ?3Z0 7n , /, l7 <cr-\\ / ^ Uu-f-T It has been known for years: that csnorvmi j=e i-piderrcs/o-vtn-i es> wrvo^r*rLk-iitn>cgt t irnt -aaesVbvAeerst-trvoes' nprrrio/^dTiuctioAnn ' Q were prone to develop a disabling lung disease. In time, this condition be came known as asbestosis and was related to exposure to high concentrations of asbestos dust. With further experience, it was found that men could work with asbestos without development of lung disease if dust concentrations were kept below a certain level. It has been generally accepted that a worker will not develop asbestosis if he is exposed to no more than 5 million particles per cubic foot of air, even if this exposure continues for his entire working lifetime. Although no cases of asbestosis are known to have occurred when exposures have been main tained at or below this level, the ACGIH (which sets the threshold limit value (TLV) in^the U. S. A. ) has indicated they intend to lower the TLV for asbestos to 2 million particles per cubic foot in an effort to increase the safety factor ll< incorporated in the limit. The U. S, Department of Labor has already issued^ 3 a regulation under the Walsh-Healy Act placing the TLV for asbestos at 2 million particles per cubic foot for public contracts in which the'y have juris diction. This concentration of dust is generally not visible in the average work area unless a beam of light causing a Tyndall effect is present. Usually-the dust concentration must be from 8-10 million particles per cubic foot (MPPCF) before its presence is visible in average .lighting conditions. Several years ago, it was reported that there was an increase in the incidence of caxerous tumors, especially of the lung, associated with asbestosis. Re cently there have been reports of some cancers occurring in individuals exposec to asbestos dust, but who have not developed clinical asbestosis. It is believed by most authorities that these cases have been associated with exposures significantly exceeding the Threshold Limit Value. A t\;;e of cancer named mesothelioma has been noted to be associated with asbestos exposure in recent years. These tumors, while rather few in number to Cate, may ocvwr in individuals with histories of only slight exposures, and that as much as twenty m forty years earlier. There is considerable evidence that crocidolile-' i.-> most trecuently associated with mesotheliomas. From the data available it appears rr.ht tile TLV ot 5 MPPCF may not be low enough to protect against mesothelioma Research on the problem continues. :U; ion Carbide's CALIDRIA Asbestos is ehrysotiie, not crocidolile. J^2 vin y fJ/ yd/ (/ UCC 023474 '' '' Fay cd 3 S t< r IT 6647.93a] lVl0.93a Asbcslos ilusl. (a' The 8-hour time-weighted aver age airborne concentration of asbestos oust to which employees are exposed shai! not exceed 5 fibers per milliliter greater than 5 microns ill length, as de termined by the membranes filter method at 400-450 X magnification (4 millimeter objective) phase contrast illumination. Concentrations above 5 fibers per milliliter but, not to exceed 10 fibers per milliliter, may be permitted up to a total of 15 minutes in an hour for up to 5 hours in an 8-hour cay, <b) Engineering methods, such as but not limited to, enclosure, vacuum sweep ing, and local exhaust ventilation, shall be used to meet the exposure limits pre scribed in paragraph (a) of this section. Where such engineering methods are not feasible, or do not otherwise reduce the concentrations below those prescribed in paragraph (a) of this section, respira tory protective devices shall be provided and used in accordance with paragraph Cc) of this section. (c)(1) <i) When the limits of ex posure to asbestos dust prescribed in paragraph (a) of this section are ex ceeded and when engineering controls required by paragraph (b) of this section are not feasible or do not otherwise re duce the concentration of asbestos dust Employment Health and Safety Guide i.-l.r amended at'Si F. R. Id 101, Aufi. 15, 1971, and at 36 /'. R. 23207, Dec. 7, 1971.] below those prescribed in paragraph (a) of this section, the employer shall re quire the use of respiratory protective de vices, The selection of respiratory protective devices shall be limited to those specified in the remaining sub> paragraphs of this paragraph <c). (li) The employer shall require that ' each employee test his respiratory pro tective device before each use in order to insure a proper fit according to the manufacturers instructions. The em ployer shall further provide for effective training or supervision of employees in the testing of respiratory protective de vices for fit before their use. <2> For an atmosphere containing not more than 25 fibers per milliliter greater than 5 microns in length over an S-hour average, or more than 50 fibers per milli liter over any period of 15 minutes, a reusable or single-use filter type respira tor, operating with negative pressure curing the inhalation phase of breathing, approved by the U.S, Bureau of Mines under the provisions of 30 CFR Part 14 (Bureau of Mines Schedule 21B>, or a valveless respirator providing equivalent protection, snail be ustc. (i For an atmosphere containing not more than 250 fivers per nuilllter greater than 5 microns m length over an B-hour aver.TM or mere than 590 fibers per m: .ifitj-r over -r,y period of 15 :nmut. a ;.uvcit fill'.-.' poative pressure res Vi 6647.93c pirator approved by the U.S. Bureau of Mines under the provisions of 30 CFR Part 14 (Bureau of Mines Schedule 21B) shall be used. d) For an atmosphere containing more than 250 fibers per milliliter greater than 5 microns in length over; an 8-hour average a type C poscuve pres sure supplied-air respirator approved by the U.S. Eureau of Mines under the pro visions of 30 CFR Part 12 (Bureau of Mines Schedule 19B) shall be used. (5) Tne employer shall establish a respirator program in accordance with the requirements of American National Standard Practice for Respiratory Pro tection Z83.2--1969. (6) The respirators provided each em ployee shall be properly inspected, cleaned, repaired and stored. (d> (1) When an employer has em ployees who are exposed to asbestos dust exceeding the limits prescribed in para graph (a) of this section and the ex posure results from the operations 'de scribed in the remaining subparagraphs of this paragraph (d), the employer shall comply with the requirements of these subparagraphs relating to the operations involved. The requirements of this para graph are in addition to those prescribed in paragraph (b) of this section. & ;2) All hand- or power-operated tools which produce asbestos dust such as, but not limited to, saws, scorers, abrasive wheels, and drills shall be provided with local exhaust ventilation and dust col lectors m accordance with the American National Standard Fundamentals Gov erning the Design and Operation of Local Exhaust Systems; ANSI Z9.2--1971. (3) Employees exposed to the spraying of asbestos or the demolition of pipes, structures, or equipment covered or in sulated with asbestos shall be provided with respiratory protective devices in accordance with paragraph <c)(4; o' this section. (e) Asbestos cement, mortar, coatings, grout, and plaster shall be mixed in closed bags or other containers. (f) Asbestos waste and scrap shall be collected and disposed of in sealed bags or other containers. (g> All cleanup of asbestos dust and blowing shall be performed by vacuum' cleaners. No dry sweeping shall be per formed. . i l'* IP 95 let) added at 36 F R. 'll'" i a 7 :J71\ ' t 6647.94 * UCC 023475 a