In a 90-day subacute oral toxicity study conducted in beagle dogs, the test substance was administered to the diet at dose levels of 2,000 5,000 or 20,000 ppm. The two highest dose levels were found to initially induce lethargy, anorexia, dehydration and emaciation. These symptoms were then followed by hyperirritability, disorientation, motor ataxia and convulsions in affected dogs. Treatment-related hematological effects were recorded on the 5,000 and 20,000 ppm dose groups. These effects included a decrease in hemoglobin, hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin. An increase in banded neutrophils was also recorded. Gross and histopathological findings included focal tubular nephrosis of the kidneys at all three dose levels. Hypercellularity of marrow elements was recorded in one animal at the highest dose level. Microscopic evaluation of brain and spinal cord revealed lead-induced lesions in six dogs (1 at 2,000 ppm, 1 at 5,000 ppm and 4 at 20,000 ppm). The lesions were attributed to hypoxia and anoxia. Regenerative changes were present that were indicative of repair.