§ 250.605. Sources of toxicity information.

 (a)  For site-specific standards, the person shall use appropriate reference doses and cancer slope factors identified in Subchapter C (relating to Statewide health standards), unless the person can demonstrate that published data, available from one of the following sources, provides more current reference doses or cancer slope factors:

   (1)  Integrated Risk Information System (IRIS).

   (2)  Health Effects Assessment Summary Table (HEAST).

   (3)  United States Environmental Protection Agency, National Center for Environmental Assessment (NCEA) provisional values.

   (4)  Agency for Toxic Substances and Disease Registry (ATSDR) Toxicological Profiles.

   (5)  California EPA, California Cancer Potency Factors.

   (6)  EPA criteria documents, including drinking water criteria documents, drinking water health advisory summaries, ambient water quality criteria documents and air quality criteria documents.

 (b)  If no toxicity values are available from sources identified in subsection (a), the person may use the background standard or meet one of the following:

   (1)  Develop for the Department’s review in the risk assessment report one of the following:

     (i)   Chemical-specific toxicity values in accordance with the methods in the most current EPA guidelines or protocols, approved by the Department, using corroborated peer-reviewed data published in a scientific journal, if they exist.

     (ii)   Toxicity values developed from appropriately justified surrogates.

   (2)  Use the minimum threshold medium-specific concentration, as the site-specific standard, with an assumed risk of 1 x 10^-5 for purposes of calculating cumulative risk for the regulated substances identified in Appendix A, Table 6.

   This section cited in 25 Pa. Code §  250.602 (relating to risk assessment procedures); and 25 Pa. Code §  250.606 (relating to development of site-specific standards).