In November 2008, traces of melamine were reported to have been found by the U.S. Food and Drug Administration in infant formula sold in the United States made by the three main American firms[52][53] — Abbott Laboratories, Nestlé and Mead Johnson — responsible for 90–99% of the infant formula market in that country.[3][52] The levels were much less than those reported in China, where levels of melamine contamination had reached as much as 2,500 parts per million, about 10,000 times higher than the recorded US levels. The safety data sheet for melamine (CAS registry number 108-78-1; C3-H6-N6) recorded the acute oral toxicity (median lethal dose) at 3161 mg/kg for a rat.