Occupational exposure to carbon/coke fibers in plants that produce green or calcined petroleum coke and potential health effects: 1. Fiber characteristics.
Carbon/coke fibers are found in bulk samples of calcined petroleum coke. Carbon/coke and other fibers, including calcium silicate, cellulose, gypsum, and iron silicate, have been found in exposure monitoring of workers who make or handle green or calcined petroleum coke. Carbon/coke fibers are not classified or regulated as carcinogens by any agency, and the available literature (summarized in this article) has not reported significant adverse health effects associated with exposure to these fibers or dusts containing these fibers. However, available epidemiological and toxicological studies have limitations that prevent a definitive assessment of carbon/coke fiber toxicity. Therefore, it is prudent to monitor and control workplace concentrations. Analyses by transmission electron microscopy (TEM) indicate that the carbon/coke fibers are amorphous, irregularly shaped, and generally rather short (94% less than 20 microm long). Nearly all carbon/ coke fibers satisfying NIOSH 7400 B counting criteria are detectable by phase-contrast optical microscopy (PCOM), which permits the use of a highly efficient sequential sampling strategy for analysis. Data are presented on the distribution of carbon/coke structure and fiber lengths and diameters. Bootstrap resampling results are presented to determine confidence intervals for structure/fiber length and diameter. Data on time-weighted average concentrations are given in a companion article, but nearly all time-weighted average carbon/coke fiber concentrations were beneath 0.1 fibers per milliliter.
Maxim
L Daniel
LD
Everest Consulting Associates, Cranbury, New Jersey 08512, USA. postsf@aol.com
Galvin
Jennifer B
JB
Niebo
Ron
R
Segrave
Alan M
AM
Kampa
Otto A
OA
Utell
Mark J
MJ
D017610:Calcium Compounds / Q000009:adverse effects; D002133:Calcium Sulfate / Q000009:adverse effects; D002244:Carbon / Q000009:adverse effects*; D002482:Cellulose / Q000009:adverse effects; D003077:Coke / Q000009:adverse effects* / Q000032:analysis; D004784:Environmental Monitoring; D006801:Humans; D007501:Iron / Q000009:adverse effects; D008855:Microscopy, Electron, Scanning; D008858:Microscopy, Phase-Contrast; D019016:Mineral Fibers / Q000009:adverse effects*; D008903:Minerals; D016273:Occupational Exposure / Q000009:adverse effects*; D010578:Petroleum / Q000009:adverse effects* / Q000032:analysis; D017640:Silicates / Q000009:adverse effects
D017610:Calcium Compounds; D003077:Coke; D019016:Mineral Fibers; D008903:Minerals; D010578:Petroleum; D017640:Silicates; D002244:Carbon; D002482:Cellulose; D007501:Iron; C031293:calcium silicate; D002133:Calcium Sulfate