Document 95GZKvV4ED86kvnXbne4oQ6D

TH-e'mOUNT SINAI NODICAL CENTER O^c CuSTa\ fc L LE' ' N;u \0XK \ > im> Mount Smji School of MedicAc The NVhjai Sirvai H<xp(*l \\ /W }i August 2, 1983 l S9ir A*>*.*? 10 *., /or Sfr,.-r l't UAJ> Mr. Chuck Scarborough Channel 4, VNBC 30 Rockefeller Plata Nev York. NT Dear Mr. Scarborough: Several weeks ago we received froa your television necuork three samples of Monokoce MX-S spray insulation, taken froa three diftctent construction sites in Nev York City. These sasples were identi fied as follows: lot SC2, lot 201 and lot 8C1. Each sample vas prepared for electron aicroscopic analysis in the saae sanner. An aliquot'was first passed through a No. 12Caesh screen for the purpose of separating finer dust frea clvrops of aaterial. This fraction uas then treated with 0.1 ooiar sulfuric acid co dissolve the gypsua present. Alter washing and drying, the aaterial was prepared for electron aicroscopic analysis by rhe "uipe-ouc'' technique. At least 20 grid openings, on twelve grids, were scanned at 13.0C0X magnification (a total of froa 2 to 3 tremolite fibers were seen for each saaple). Their iden tities were established by chemical and ultra-structural characteri sation. These fibers represent only a trace of the total aass of the aliquot examined. While the precise quantity of tremolite present in each saaple is difficult co oeasure. fr aay be estimated to be on the order of cen-thousandths of a percent, or possibly parts per ailllon, by volvoac. On the basts of this aineralogical cha r ic te r i ta c ion, I would cor. side; these three samples of Monokote MX-J co be virtually free of asbescifora alneral fiber. ANR : \a N Arthur N. Rohl, Ph.D. Assistant Professor. Mineralogy 10003193