However, environmental chains of events can end in serious molybdenum-related health consequences. In 1996 in Sweden an increase in acid rain near Uppsala caused a depletion in the natural foods of moose in nearby rural areas. This caused the moose to venture into the fields of oat farmers who had been heavily liming their soil to compensate for the effect of the acid. The lime caused changes to the levels of cadmium and other trace metals in the soil, causing the oat crops to uptake trace molybdenum in large quantities. Ingestion of the oats by hundreds of moose brought on a severe disturbance in the ratio of molybdenum to copper in their livers, which caused emaciation, hair discoloration, ulcers, diarrhea, convulsions, blindness, osteoporosis and finally heart failure.
Maximum exposure should not exceed 15 milligrams per cubic meter in a 8 hour day, 40 hour week.