...A man whose hands and forearms were heavily exposed to mineral oil hydraulic fluids in his job developed weakness in his hands. This effect was probably caused by one of the organophosphate ester additives of the mineral oil hydraulic fluid. The skin and eyes of animals were red and swollen after contact with certain mineral oil hydraulic fluids and polyalphaolefin hydraulic fluids. Animals breathing very high levels of polyalphaolefin hydraulic fluids became drowsy and had congested lungs and trouble breathing. We do not know if mineral oil hydraulic fluids or polyalphaolefin hydraulic fluids will cause birth defects, reproductive effects, or cancer.
...Studies in animals suggest that if you breathe or swallow large amounts of certain organophosphate ester hydraulic fluids, you may have nervous system problems. Certain organophosphate ester hydraulic fluids affect the nervous system of animals in two different ways. The first type of effect occurs within a few hours of breathing, swallowing, or skin contact. The organophosphate ester part of the hydraulic fluid rapidly inhibits the activity of important enzymes in the nervous system causing multiple symptoms including tremors, sweating, diarrhea, and difficulty breathing. The second effect involves damage to nerves. The symptoms of this type of damage are general weakness, weakness of the arms and legs, and paralysis. These symptoms of nerve damage can occur several weeks after exposure has stopped. If you have been exposed once to organophosphate ester hydraulic fluids, the symptoms of enzyme inhibition will disappear before the weakness occurs. Not all types of these fluids cause both types of nervous system damage. In animal studies, not all animals that have symptoms of enzyme inhibition have nerve damage. Both of these types of nervous system damage can occur after one or several exposures.
