Document JryvLK8NO2jXN2bDjeZqXQoJB

4 f vAtmr.a UUtugcr / February.10, 1975 t Mr. L. W.' Anderson Central Research Laboratory Since the acquisition by ASARCO of the Cement Asbestos Products Company (CAPCO) in the latter part of 1974, asbestos particle counting has become more commonplace in our labora tory. The sample types are primarily discharged water and filter samples from workroom atmospheres. We are currently using*phase contrast microscopy to count asbestos-like particles. We .count one hundred fields of known area under the microscope and then relate the average concentration of particles/field back to the area of the total filter. Only fibers longer than 5 ym are counted. The filters represent either a"'known volume of "water or a known volume of air If Tom Sheehy, Tom Kartelias, and you would be agreeable we would like to have a few samples that we have run checked by electron microscopy -and also to have the particles characterized"'as to "their" form (i.e. chrysotile, crocidolite, amosite, etc.). This is assuming that it is possible. We can also provide you with several round-robin samples and their particle counts to practice on. These round-rebin samples are part of the KIOSK Proficiency Analytical Testing Program which v;e participate in. The check samples will be pieces of the same filters we counted for water and airborne particulate. Part of our interest in this project stems from the Envi ronmental Protection Agency's use o electron microscopy in their counting. They_ will be sampling at CAPCO-Ragland in the near future and we wanted some feeling as to the comparison between the two methods. We will wait for your reply before forwarding any samples. DAR/bjs cc: Dr.VKudryk MOVarncr Donald A. Robbins Chief Chemist ASARCO ALV 0000275