HEALTH EFFECTS|Environmental Defense's Custom Hazard Identification

A small number of Toxic Release Inventory chemicals have not been assigned human health hazard identifications based on Environmental Defense's review of scientific and regulatory literature and analysis of toxicological databases. Environmental Defense conducted a customized, supplementary review of TRI compounds with reported environmental releases to identify any remaining potential human health hazards. We determined that there were three potential explanations for why a substance listed under TRI might be missing a human health hazard identification:

1) TRI lists a category or class of compounds, rather than a specific chemical that has been the subject of toxicity evaluations. For example, the TRI category of "certain glycol ethers" has not specifically been the subject of hazard identification efforts, although many glycol ethers covered by this category have been characterized as human health hazards. Since the class of glycol ethers includes recognized developmental and reproductive toxicants, the TRI category can be considered suspect for these health effects. Environmental Defense's Member Class documentation explains how and when Scorecard assigns classes of compounds hazards based on their constituent members. In some cases, TRI categories are not known to contain recognized hazards, although constituent members may be suspected of harming human health. Since Scorecard does not designate a class as suspect based on members being suspect, these TRI categories do not have any identified health effects.

2) No toxicological data are readily available that characterize the potential human health effects of a TRI chemical. Environmental Defense widened its search for hazard identification data for all TRI chemicals that are not assigned health effects in Scorecard. We examined sources that were not generally relied on for hazard identification because they do not support abstracting hazard classifications for large numbers of chemicals. Many references do not utilize consistent hazard descriptors or summarize hazard identification evaluations in tables, so they could not be utilized as a hazard identification source without chemical- by-chemical review. "Last resort" source of hazard identification include several US EPA databases: Integrated Risk Information System (IRIS), Health Effects Assessment Summary Tables (HEAST) and Office of Pesticide Programs Databases (OPP). Last-resort sources also include the California Air Resources Board's Toxic Air Contaminant Identification Summaries (TAC), and factsheets and material safety data sheets available on the internet.

3) The TRI chemical is an environmental hazard, but not a human health hazard. For example, several chlorofluorocarbons (CFCs) do not directly pose human health risks, but are listed under TRI because of their capacity to deplete the stratospheric ozone layer. On the basis of available data, such chemicals do not appear to pose direct human health risks.

The following CFC chemicals with substantial reported environmental releases have not been assigned human health effects:
2-chloro-1,1,1-trifluorethane (75-88-7)
1,1,1-trifluoro-2,2-dichloroethane (306-83-2)
1-chloro-1,1,2,2-tetrafluoroethane (354-25-6)
2-chloro-1,1,1,2-tetrafluoroethane (2837-89-0)
1,2-dichloro-1,1,2-trifluoroethane (354-23-4)