Toxicopathology of oilfield poisoning in cattle: a review

The toxicologic pathology of petroleum and oilfield-related chemicals is reviewed, and a field guide for toxicopathologic evaluation of cattle is given. Cattle will voluntarily ingest petroleum and chemicals used in the exploration, production and transportation of crude petroleum. Variability in chemical composition of petroleum from different fields will alter the type and severity of lesions observed. When airborne pollutants are present, cattle are continually exposed and make excellent sentinel animals. The lung, kidney, liver, gastrointestinal tract, heart and brain are target organs for petroleum hydrocarbons. Exposure to elemental sulfur can produce pulmonary pathology. Sulfur-containing gases are irritating to the mucosa of the eye and respiratory tract. Arsenic and lead cause lesions in the gastrointestinal tract, brain, liver and kidney. Glycols are hepato-, nephro- and neurotoxic, and oral exposure to diethylene glycol produces corneal lesions. Invert drilling fluids are fetotoxic. Nonpesticide organophosphate esters target the peripheral and central nervous systems. Toxicopathy is a strategic tool in the diagnosis of intoxications occurring in cattle after exposure to oilfield chemicals. Cattle are sensitive to oilfield pollutants and are a useful biomonitoring species.