Document 0qzGKBzML0vZY05bZVJ6Y3ZKn

FROM thomAS B. BONNEY PITTSBURGH PLAINTIFFS EXHIBIT &8a tr- INDUSTRIAL HYGIENE COMMITTEE CHAIRMEN September 25, 1964 Re: INDUSTRIAL HYGIENE NEWSLETTER MARINITE _______ Some of you are aware that in recent weeks there has been a flurry of correspondence within Alcoa and between Alcoa and Johns-Manville concerning one of the latter's products, Marinite. The renewed interest resulted from our Research personnel's advising us that the earlier information obtained from Johns-Manville upon which our Marinite newsletter of May 4, 1964 was based, was erroneous. Johns-Manville was pleased to straighten out this misinformation and assured us that this latest information is the correct informa tion. We, in turn, are pleased to pass along our revised comments in what we hope will be the last newsletter regarding Marinite. J-M categorically denies the presence of epoxy resins in Marinite. It consists mainly of asbestos fiber. Also present are diatomaceous earth and a calcium silicate binder. Because they are minor compo nents and of lesser toxicological significance, the latter two com ponents need not be considered when evaluating the hazards and recommending safe procedures for handling Marinite. From a toxicological standpoint and for all practical purposes Marinite can be considered to be asbestos alone. Therefore, timeweighted daily average exposures to the dust should be kept below 5 million particles per cubic foot. In addition, even though average eight-hour exposures are below 5 mppcf, regardless of their brevity, no exposures should exceed 20 mppcf. This means that wherever the sawing of Marinite is a regular operation the saw should be ventilated. Only if the sawing operation is infrequent and brief would respiratory protection be considered an adequate substitute. It should be kept in mind that if the saw used to cut Marinite is also regularly used for dry cutting other refractory material there is all the more reason for providing it with exhaust ventilation. Because there are no epoxy resins in Marinite, the dermatitis potential of Marinite is minimal and the possibility of producing asthmatic-like reactions in sensitive individuals is highly unlikely. The dust, however, is capable of irritating the skin and the mucous membranes (especially in the nose) of some people. Therefore, the use of long sleeves on the sawing job and the need for washing to remove the dust deposited on the skin will be largely a personal matter. We wish to emphasize that the absence of epoxies in Marinite does not necessarily mean the elimination of the need for ventilation. It means merely that the short-term penalties one might pay for not having appropriate control measures are lessened. APC 001239 ALCOA Industrial Hygiene Committee Chairmen Sept. 25, 1964 Paae 2 Enclosed you will find the latest of the Hygienic Guide Series: Chlorobenzene, o-Dichlorobenzene, p-Dichlorobenzene, Ethyl Acetate, Methyl Acetate, Phosphine, Tellurium, Trichloroethylene. ^i* Pw T. B. BONNEY ' TMB: OB line Is. cc/encls: Plant Physicians G.H.Farrah. J.M.Plunkett, ARL Colwell. L.V.Cralley, file cc: K.J.Brondyke, M.J.Caprio, ARL M.E.Gantz,Jr., Pgh. F.H.Illig, Pgh. APC 001240 l-dustrial Hygiene Coanittee Chairmen 0">C, V^erj^o . V.M.*i i iiajns \ . A. rlayea Alcoa. Fab Alcoa Sa. Bad in V. 5. Barr c. L. Rover 0. Turner M . A. Semken rl . B. Porter Massena Pt. Coaf. Sa. P t. Coaf. Ref. Rockdale Vancouver R L. Parsons w 0. 3runo --r1 a Kukla 1 Levin Warrick Wenatchee Chicago Cleveland ' . ^ . Harvey Cressona Davenport A. M. Miller J. ^ "oulke tk* s. Chaabers u. Edgewater Edison Laf**tte Arthur Hartwell f Lancaster n R. c. Hospes Rlchaond * i 1. McClintock Vernon APC 001241