Results of First Round of Chemicals Eligible for Prioritization for Consideration of Carcinogenicity Evaluation
The Office of Environmental Health Hazard Assessment (OEHHA) is responsible for the implementation of the Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65). Under the statutes, a chemical may be identified as "known to the State to cause cancer" based on the rendering of an opinion by the OEHHA Science Advisory Board's Carcinogen Identification Committee (CIC) that a chemical has been clearly shown, through scientifically valid testing according to generally accepted principles, to cause cancer, or identified through either of two administrative listing processes. In order to implement the statutes, OEHHA developed a database for chemicals that have been nominated or suggested for consideration under Proposition 65. The database contains several hundred entries based on information taken from the scientific literature (including published lists and databases), nominations from members of OEHHA's Science Advisory Board, other state agencies, the scientific community, and the general public. The basis for nominations to the database may be, for example, positive animal cancer bioassays, epidemiological studies, structural and biological activity similar to known carcinogens, or genotoxicity. The database contains chemicals with widely varying degrees of toxicity, production, use, and exposure information. To enhance the quality of the database, the chemicals are tracked and their toxicity data updated as new information becomes available.
For the pilot random selection, OEHHA conducted an initial screen of the database for chemicals with toxicity information entered into the toxicity field of the data entry sheet. Eighty-five chemicals were identified that could potentially be considered by Science Advisory Board. Because OEHHA typically organizes its workloads into batches or groups of 10 to 20 chemicals, we randomly selected from the file of 85 chemicals three sequential batches of 10 chemicals each. Each chemical in the batch of 10 will receive a screening toxicity evaluation as described in the document entitled "Procedure for Prioritizing Candidate Chemicals for Consideration Under Proposition "States Qualified Experts."
The screening toxicity evaluations are based on a brief review of the readily available toxicological information (e.g., scientific reviews and other secondary literature) and reported in a data summary. The draft data summaries and draft priority rankings are released for scientific review and public comment, including a public workshop. Chemicals receiving a final ranking as a "high" priority will be considered first by the CIC. Chemicals not ranked as "high" will be returned to the data base and continue to be tracked and updated. Typically, these chemicals would not go before the CIC unless new and significant information becomes available that would change the relative ranking or until after all other chemicals assigned a high priority in database have been brought before the CIC. To facilitate the Committee's consideration, hazard identification documents (HIDs) are prepared that summarize the scientific evidence on the carcinogenicity of the chemical, typically taken from the primary literature (i.e., original scientific articles). Initially, HIDs will only be prepared for those chemicals that are ranked as "high" priority.
For the pilot random selection process, OEHHA developed a series of 500 randomly generated numbers shown in Table 2 using Microsoft Excel. On August 4, 1997, OEHHA inserted the 85 alphabetically arranged chemicals shown in Table 1 into Table 2 to determine a numerical reordering of the 85 chemicals. This resulted in a "shuffling" of the alphabetical list. The relative position where the alphabetical listing in Table 1 was inserted into the series of random numbers in Table 2 was based on the sum of the first three Super Lotto numbers
Using the sum of the first three numbers (31, 2, 50) drawn from the California Super Lotto on August 2, 1997, the seed number for the first round pilot random selection is 83. Beginning with the 83rd number (190) and ending with the 167th number (234) on Table 2, each of these 85 chemicals had a unique random numerical value assigned it. These 85 assigned random numbers, and corresponding chemicals, were reordered according to increasing value. The lowest 10 numerical values will constitute the chemicals in the first batch (RS-1), the next 10 lowest numbers the second batch (RS-2), and the next 10 lowest numbers the third batch (RS-3). The results of the random selection and assignment of chemicals to each of the three batches are found on Table A: Pilot-First Round Randomly Selected Candidates on OEHHA's Home Page. The remaining 55 chemicals will be returned to the random selection file and combined with the results of the next screening of the data base. OEHHA anticipates similar screenings and random selections at 3- to 4-month intervals.
OEHHA is committed to an open and public process in the implementation of Proposition 65. The posting of the initial alphabetical listing in Table 1, the list of random numbers in Table 2, and the results of the random selection in Table A and prioritization of chemicals for consideration by the CIC is part of that process.
For inquiries related to Table 1, Table 2 and Table A please call or write to:
Reproductive & Cancer Hazard Assessment Section, OEHHA
1515 Clay St 16th Floor
Oakland, CA, 94612
Telephone: (510) 622-3170
Fax: (510) 622-3218
For inquiries on Proposition 65, please call or write to:
Proposition 65 Implementation
OEHHA
Post Office Box 4010
Sacramento, CA 95812-4010
Telephone: (916) 445-6900
