34 Pa. Code § 323.3 – Environmental hazards.

(a) Hazardous substances which are considered environmental hazards because of their particular or extreme properties pose a danger if released into the environment are contained in an Environmental Hazard List. Only substances on the Hazardous Substance List in Appendix A which have the letter ‘‘E’’ are part of the Environmental Hazard List.
(b) The Department will evaluate the appropriateness of designating hazardous substances as environmental hazards based on the following criteria:
1. (1) The substance shall be one which is on the Department’s Hazardous Substance List.
2. (2) The substance shall be regulated under Federal, State, county or municipal environmental statutes.
3. (3) The substance shall pose a danger if released into the environment in that it shall be considered toxic, hazardous or it shall be a contaminant subject to Statewide standards for emissions or discharges under current environmental statutes regulating the substance.