April 27, 2001

Science Advisory Board
Executive Committee Members
U.S. Environmental Protection Agency
1200 Pennsylvania Ave., NW
Washington, DC 20460

Dear SAB Executive Committee Chair and Members:

   In a public teleconference on May 23, the SAB’s Dioxin Reassessment Review Subcommittee ("DRRS") discussed further editing of its most recent draft report prior to submission to the SAB Executive Committee for its May 15 meeting.

   The draft report under discussion stated: "Some Members support the classification of TCDD as a human carcinogen. However, most DRRS Members do not support the classification of TCDD as a human carcinogen, citing . . . ." During the teleconference, a decision was made to change "most DRRS Members do not support" to "about half the DRRS Members do not support". (Underlining added.) We are objecting to that change because it was absolutely clear from the discussion during the teleconference that the change is inaccurate and likely to be misleading and will place into question the SAB’s reputation for transparency and accuracy in its reports.

   During the teleconference it was disclosed that very recently the DRRS members had been polled to obtain a new vote count on this issue. The vote count, as stated during the teleconference, was 9 against classification as a human carcinogen, 7 supporting such a classification, 3 "neutral" or abstaining, and 1 who had not responded.¹

   Thus, it is clear that a majority of those voting for or against were against classification as a human carcinogen, while only about one-third of the Members were willing to support it.² The vote also showed that a majority of the total 20-member subcommittee "do not support" such a classification, since a vote of neutral or an abstention must be considered an absence of "support". The vote thus reaffirmed the original draft statement that "most" Members "do not support" such a classification, since a total of at least 12 Members are not willing to support the classification, while only 7 support it. Later in the teleconference, the Members agreed that "most" would be an accurate description of an 11-6 vote on another issue.

   If the final report approved by the SAB Executive Committee states that "about half" rather than a "majority" or "most" DRRS Members do not support classification as a human carcinogen, many agency officials, other readers, and advocacy groups are likely to interpret or represent such a statement as meaning that less than, or not more than, half, and certainly not a majority, did not support classification as a human carcinogen; and conversely, that at least half, and perhaps a majority, supported such a classification. The statement would therefore be misleading by not accurately representing the weight of opinion, and should be clarified.

   We believe that it is the responsibility of the DRRS Chair, the DFOs, and the Executive Committee to ensure that the views of committee Members are presented in a manner that is clearly accurate and not likely to be misinterpreted or to be subject to misrepresentation. We therefore strongly recommend that "about half" be revised or clarified to convey accurately the actual weight of opinion – which in this case would mean stating that a "majority" or "most" of the DRRS do not support classification of dioxin as a human carcinogen.