Document e1m6mrn9k5DENbLGmaDbE5rqM

FILE NAME Talc TALC DATE 1973 Aug 31 DOC TALC455 DOCUMENT DESCRIPTION Memo RE Proposed Specifications on Talc 22) Manville Internal Correspondenci Internal Internal Internal Internal | Corespondenci Correspondenci Corespondenci To P. A. Martinson 2 West From R. S. Lamar D Center Copies e Dato August 31 1973 Subject FDA PROPOSED SPECIFICATIONS ON TALC Our memo to you dated August 29 1973 was an charged exercize It was intended to be just that in an effort to the alert all involved as to the critical nature of we now face battle This present memo on the same subject is more calm assessment of the same situation Given below are our analyses of some of the numbers presented by the FDA in their proposed speci- through fication and test method Sid speil suggested that we go | thisparticular exercize It proves to be very produc- tive : There are glaring inconsistencies that make the test method and specification completely incompatible On the one hand the FDA states that talc shall be 99.9 percent pure insofar as tremolite is concerned and 99.99 percent pure insofar as chrysotile is concerned On the other hand in their proposed test method they permit a maximum of 1000 tremolite fibers and 100 chrysotile fibers Only fibers 5 inconsistency where ambiguity microns or greater in length with an aspect ratio of 3/1 or greater are counted Here is the involved complete and is If we assume that FDA is going to base their requirement on percent purity and that they really mean 99.99 percent pure insofar as chrysotile is concerned then up to 0.01 percent chrysotile would be permitted In terms of fiber count then the number of fibers permitted would depend on the size of the fiber The smaller the fiber the less they weigh and weight more would be permitted For example 38,500 fibers 0.5 x 5.0 microns would amount to 0.01 percent by If we assume a larger fiber size at 1.5 x 50.0 microns then 435 fibers by percent microscopic count would amount 0.01 These numbers are far from the 100 maximum mentioned in the test method For tremolite the numbers are even more startling The specification calls for the tale to be 99.9 percent free of tremolite In other words up to 0.1 percent tremolite would be permitted This would mean that on a weight percent basis 000083 | Page 2 P. A. Martinson | August 31 1973 ; the talc could contain up to 345,000 tremolite particles x 5.0 microns in size 3,850 tremolite particles 0.5 1.5 x 50.0 microns in size these numbers are Again quite different from the 1,000 1,000 maximum described the FDA test method Looking way at these inconsistencies the opposite terms of indicated percent purity as defined by number counts of 1,000 and 100 for tremolite and chrysotile respectively data are mind boggling For example 1,000 fibers of tremolite 0.5 x 5.0 microns in - size works out to only 0.0003 percent by weight The talc would have to be 99.9997 percent pure Another example 1,000 fibers of tremolite 1.5 50.0 micronisn size amounts to 0.03 percent by weight In this case the talc would have to be 99.97 percent pure These are quite different from the 99.9 percent purity mentioned in the proposed specification Looking at chrysotile the same fib 100efr ibes rs 0.5 x 5.0 microns by amounts to 0.00003 percent weight With fibers 1.5 x 50.0 microns in size the weight is 0.002 percent In other words purities of 99.99997 percent and 99.998 percent would be required These numbers are really boggling It is almost impossible to obtain reagent grade analytical chemicals of this state of purity Here are a few examples Reagent Baker Analyzed percent NaCl Grade Sodium Chloride is only 99.9 99.9 . Baker Analyzed Reagent percent Na2CO3- Baker Analyzed Reagent percent CaCl2 Baker Analyzed Reagent percent KNO2 Grade Sodium Carbonate is only 99.7 , Se Co, mo Grade Calcium Chloride is only 98.4 oo Grade Potassium Nitrite is only 98.8 e Baker Analyzed percent KOH Reagent Grade Potassium Hydroxide is only 85.2 fifth boggling The FDA is calling for talc purities out to the point Truly mind decimal RS R. S. Lamar IF See Distribution on Reverse Side 000084 CC W. L. VanDerbeek J. Sharratt H. R. Keefe 7. Pundsack S. W. R. Speil . C. Streib P. Carter E. Parker F. J. Solon ~ 2 West . 22 West - 2 West 7 R Center ~ & Center ~ R Center - 5 West - 5 West - West SL 000085