a subset of workers was followed after exposure to polychlorinated biphenyls ( pcbs ) , dioxins , and furans in an occupational medicine clinic setting . patterns of pcbs found in adipose tissue resembled the pattern seen when soot from the incident or aroclor 1254 was examined by gc - ms . 
 adipose tissue also revealed levels of hepta- and octachlorinated furans and dioxins as high as 8400 ppt in one repeatedly exposed worker . 
 control fat from patients with no known exposure to furans or dioxins was usually in the several hundred parts per trillion range for these isomers , but slightly over 2000 ppt in one sample . 
 electron microscopic analysis of liver biopsies from three patients who developed mild elevations of hepatic enzymes in their serum revealed morphologic alterations in some ways similar to those seen in animals after feeding experiments with pcbs , dioxins or the binghamton state office building soot . 
 these include pleomorphic mitochondria , giant mitochondria , prominent dense mitochondrial granules , cristae parallel to the long axis of the mitochondria and crystalline structure within same mitochondria as well as lipid droplets in liver cells and slightly dilated smooth endoplasmic reticulum.imagesfigure 1.figure 2.figure 3.figure 4.figure 5.figure 6.figure 7.figure 9.figure 10.figure 11 .