In Male Weanling Fischer 344 Rats (Final Report) (3 Parts) W-Attachments & Letter Dated 01/09/92; 02/28/83; EPA Doc. No. 88-920000641; Fiche No. OTS0535236 Melamine (CAS No. 108-78-1) was evaluated for subchronic dietary toxicity. The test substance was administered in the diet of male weanling Fischer 344 rats (40/group, except for 19 animals in the 2,000 ppm group) at concentrations of 0, 2,000, 4,000, 7,000, 10,000, 13,000, 16,000, or 19,000 ppm for 4-weeks. At the 16,000 and 19,000 ppm dose-level, treatment-related effects included a significant decrease in body weight gain. All dose levels exhibited increased water intake and decreased food consumption early in the exposure period, an increase midway through the exposure period, and a decrease in the latter part of the exposure period. Clinical signs included a dose-related increase in piloerection, lethargy, bloody urine spots in the cage and on the pelage of animals, and chromodacryorrhea. Necropsy findings concluded a treatment-related incidence of urinary bladder calculi at 4,000 ppm and above, and urinary bladder hyperplasia at 1,000 ppm and above. It was concluded that the NOEL was estimated to be 2,000 ppm.