Potential inhalation exposure of workers involved in clean up operations were investigated in the aftermath of a fire and explosion among 40,000 drums of unlabeled chemical wastes in Elizabeth, New Jersey. Forty seven personal air samples and 45 area samples were collected to measure the potential inhalation exposures. Samples were typically of 7 to 8 hours duration. Multiple screening media were used because waste materials were unknown and worker exposures were varied. No measured concentrations of single chemical substance approaches a recommended OSHA or NIOSH health effects criterion. Aluminum (7429905), calcium (7440702), iron (7439896), phosphorus (7723140), toluene (108883), and xylene (1330207) were found in more than 50 percent of the personal and area air samples. More than 50 percent of workers monitored had potential additional exposures to chromium, mercury, magnesium and sodium compounds. The authors state that this study suggest that in the presence of unknown hazardous wastes, which are unconfirmed or may be released by container failure, respiratory and full body protection from waste contact is necessary.