Syngenta Crop Protection, Inc. received on Saturday, December 2, 2000 your letter of December 1 and a copy of the November 30 USEPA Preliminary Human Health Risk Assessment. As requested in your letter, this document and attachments comprises our formal response to the HED's Preliminary Human Health Risk Assessment and associated documents. This summary, which has been revised, is contained in the next section of our comments. In the Attachments to the comments are included the following. Information clarifying agricultural practices and atrazine use; a presentation of time weighted data for the deterministic assessment; probabilistic assessment for diet and water in higher exposure CWS; a position paper titled 'Use of a 5% Factor Applied to the Application Rate for Assessment of Hand-to-Mouth Exposure to Turf Treated with Atrazine'; a timeline for submissions for ongoing studies.