An industrial hygiene survey was conducted at the Memphis Tennessee plant during the week of May 9th, 1977 by Neal R. Netzel, Industrial Hygienist, Environmental Health and Hygiene Department, to determine airborne concentrations of hexachlorocyclopentadiene (Hex) and to determine employee exposure to carbon tetrachloride. Preliminary sampling was also performed for heptachlor and endrin residues in food consumption areas and for airborne heptachlor concentrations in the catalyst drumming area. The Environmental Science, Research Department requested that air samples be collected in suspected high exposure areas of the Hex-PCL unit. Results of three of the air samples indicated levels of Hex in excess of the threshold limit value (TLV) recommended by the American Conference of Governmental Industrial Hygienists. Each of those samples were collected downwind of suspected emission points and is not indicative of actual worker exposure. The remaining samples were below the TLV, including samples of a process operator and the unit control room.