Metal Washing Fluid
Metalworking fluids (MWFs) are used to reduce heat and friction and to improve product quality in industrial machining and grinding operations. There are numerous formulations and complex mixtures of oils, emulsifiers, anti-weld agents, corrosion inhibitors, extreme pressure additives, buffers, biocides, and other additives. In use, the fluid complexity is compounded by contamination with substances from the manufacturing process. Furthermore, water-based metalworking fluids support microbial growth, which introduces biological contaminants (such as bacterial and fungal cells or cell components and their related biological byproducts such as endotoxins, exotoxins, and mycotoxins). Workers can be exposed to the fluids by breathing aerosols generated in the machining process, or through skin contact when they handle parts, tools, and equipment covered with the fluids.
Metal Washing Fluid: non-specific symptoms
A Carrier air conditioner plant had complaints from numerous workers. ICTM staff, both industrial hygiene and medical, toured the facility, performed environmental sampling, and conducted interviews with the workers. The sampling results did not indicate exposures at levels which posed a serious health risk; however, we make some operational recommendations. We met with the medical director and the workers and reviewed our findings, including our recommendations. Our physician addressed all questions from concerned workers. In the end, no serious illnesses were found and the complaints ended.
Metal Washing Fluid: hypersensitivity pneumonitis
One hundred metalworking employees sued for metal-washing fluid claims. Local physicians had treated three employees diagnosed with pneumonia, two of whom had been hospitalized. A local pulmonologist, who examined all three, later decided that, since they all worked at the same metalworking facility, something at the facility had caused their lung problem which he labeled a hypersensitivity pneumonitis. This physician then visited the plant and interviewed several employees, sharing his belief about the cause of the workers' recent illnesses. Soon there were many employees complaining of respiratory symptoms, seeking medical care and filing claims.
ICTM was asked to perform an objective evaluation of the causation alleged. We investigated the facility and the various locations and job duties of asymptomatic, healthy workers, as well as ill and symptomatic, workers. We then reviewed all of the records, the exposures, the industrial hygiene data and the testimony of opposing experts. IME's were arranged. There was no relationship between illness, symptoms, job duties, exposures, or areas of the work facility. Careful analysis of their medical records and diagnostic testing revealed no objective support for the diagnosis of hypersensitivity pneumonitis. The National Institute of Occupational Safety and Health (NIOSH) also investigated, performing a Health Hazard Evaluation (HHE) of the facility and its employees. Their conclusion matched that of ICTM.
