Communities near toluene diisocyanate sources: an investigation of exposure and health

Abstract

Toluene diisocyanate (TDI) is a well-known cause of occupational asthma, but we know little about the potential for exposure and health effects among residents who live near facilities that release TDI. In the mid-1990's, the North Carolina Department of Health and Human Services and the Agency for Toxic Substances and Disease Registry investigated exposures to TDI and health outcomes in one community, which left some unanswered questions. This crosssectional study evaluated the potential associations between living near a TDI source and the prevalence of three variables: asthma or asthma-like respiratory symptoms, antibodies specific to TDI, and verifiable levels of TDI in residential air. Results among North Carolina residents living near such facilities (five target communities) were compared with the results from residents living further away (five comparison communities). Overall, the prevalence of reporting either asthma or asthma-like respiratory symptoms was higher (odds ratio ¼ 1.60; 95% confidence interval ¼ 0.97-2.54) among residents in target communities than those in comparison communities. However, this difference was not statistically significant. Symptom prevalence varied greatly among the community populations. The prevalence of respiratory symptoms was higher near facilities with historically higher TDI emissions. Among the 351 participants who provided blood samples, only one had immunoglobulin G specific antibodies to TDI. This participant lived in a target area and may have had non-occupational exposure. TDI was detected at an extremely low level (1 ppt) in one of the 45 air samples from target communities. One ppt is one-tenth the EPA reference concentration. Overall, air sample and antibody test results are not consistent with recent or ongoing exposure to TDI.

Risk factors for nonwork-related adult-onset asthma and occupational asthma

“…Road traffic emissions are thought to induce bronchial hyperresponsiveness, leading to variable airway obstruction [66]. Toluene diisocyanate (TDI), a known cause of occupational asthma, has also been implicated in the development of nonwork-related asthma in individuals living close to the workplaces that release TDI [67].…”

Viability of cultured human skin cells treated with 1,6-hexamethylene diisocyanate monomer and its oligomer isocyanurate in different culture media

“…The annual production of isocyanates worldwide was about 4.4 million metric tons in 2002 4 and, currently, an estimated 440,000 workers are exposed to isocyanates in the United States 5 – 7 . Exposures in the general population can occur from contact with isocyanate-containing consumer goods (e.g., Gorilla glue ® ), slow-curing isocyanate coatings, materials used in housing construction, in outdoor areas near industrial sites where isocyanates are used in manufacturing, or in neighborhoods surrounding auto-refinishing businesses 8 – 10 . While inhalation exposure to isocyanates has been considered the most important route through which allergic sensitization may occur, animal studies have shown that skin exposure can result in respiratory sensitization 11 , 12 .…”

Characterization and comparative analysis of 2,4-toluene diisocyanate and 1,6-hexamethylene diisocyanate haptenated human serum albumin and hemoglobin

“…Although most reported cases of isocyanate sensitization occur at workplaces 13,14 , it has been suggested that non-occupational exposure to the general public may also occur through use of “do-it-yourself” free diisocyanate containing commercial products such as polyurethane foams and sprays 15,16 . Once allergic sensitization to isocyanates occurs, asthmatic reactions may be triggered by exceedingly minute concentrations of isocyanates 5,17,18 .…”