Preventing Health Hazards from Metal Working Fluids

Metal working fluids used without controls.

More than 100 million gallons of metal working fluids (MWFs) are produced every year, and more than 1 million employees are exposed to these MWFs. NIOSH issued guidance on recommended exposure limits (RELs) and controls for MWFs in 1998, but continues to find employees exposed to airborne concentrations of MWFs above the RELs and employees with respiratory and skin problems of the types associated with MWF exposures.

MWFs are used to lubricate, cool, prevent corrosion of, and remove chips from tools and metal parts during grinding, cutting, or boring operations. There are several types of MWFs: straight or soluble oils, semisynthetic oils, and synthetic oils. Exposures to MWFs can occur through inhaling aerosols, skin contact with contaminated surfaces, and splashing of fluids. Employees who have been exposed to MWFs often report skin disorders (skin irritations, oil acne, and rashes); eye, nose, and throat irritation; and respiratory symptoms (cough, asthma, or other breathing problems).

In 1998, NIOSH issued RELs of 0.5 mg/m³ for total MWF particulates and 0.4 mg/m³ for the thoracic particulate mass, as a time-weighted average concentration for up to 10 hours per day during a 40-hour work week. (read more of the NIOSH article here...)