Hazard Identification

The hazard identified with this particular equipment manufacturing operation involved employee exposure to contaminated metal removal fluids in the automotive transmission machining plant. In 2002, an employee reported to the plant medical department with complaints of respiratory illness while working in machining plant. The employee was working in a machining department where metal removal fluids (MRF) such as lubricants and coolants were utilized in production processes.

A subsequent medical examination confirmed that the employee was diagnosed with occupational hypersensitivity pneumonitis (HP). The employee received medical treatment, was placed on medical leave, and an investigation of the cause of the disease was undertaken. Hypersensitivity pneumonitis is a serious lung disease associated with exposure to microbiologically-contaminated aerosols of some synthetic, semi-synthetic and soluble oil metalworking fluids. In the short term, HP is characterized by coughing, shortness of breath, and flu-like symptoms (fevers, chills, muscle aches, and fatigue). The chronic phase (following repeated exposures) is characterized by lung scarring associated with permanent lung disease.

Hazard Intervention

The company identified the hazard as microbiological contamination of the metal removal fluid. The abatement approach was to change the type of fluid in use and implement a comprehensive MRF Control Plan that provided for proper selection of metal removal fluids, development of efficient coolant and machine maintenance schedules, and design of effective ventilation systems to maximize control of coolant aerosols.

The initial study and completion of IH risk assessments did not identify a clear relationship between known air contaminants in the work environment and the respiratory disease. Therefore a multifunctional task force was created, with the primary objective to eliminate the risk of respiratory disease (HP) associated with metal removal fluid (MRF). The task force represented the following: division and plant functions, corporate/plant IH, corporate research and development IH, plant union S&H and IH, division/plant medical, corporate/plant environmental engineering and chemical management, plant manufacturing leadership, manufacturing engineering, and maintenance. The task force conducted numerous exposure assessments, research studies, production process changes, and maintenance process improvements.

Impacts of the Intervention

There were many positive health, business, and risk management benefits that resulted from the implementation of the comprehensive MRF Control Plan. Health improvements resulted from the intervention because the air contaminant exposure associated with MRF machining was eliminated or reduced and employees were no longer directly exposed. No further cases of HP have been reported in the four years following the intervention. Employee respiratory complaints were eliminated or reduced. Employees were healthier, happier, and more comfortable in the workplace. Employee morale increased significantly, improving the trust and confidence of employees in the S&H program.

The business process was improved as tooling life was extended and therefore tooling costs were reduced. Many risk management benefits resulted from the intervention, including enhanced relationships between the division and plant union management. Management and engineering systems to support MRF S&H goals were enhanced. Another benefit involved the development of improved bio-stable coolant strategies.

Financial Metrics

As part of the value study, a retrospective analysis was conducted with an incremental approach to reduce workplace illnesses, and improve the risk management and business processes. After using the Value Study Data Collection Tool and entering the data in the ROHSEI software, the net present value (NPV) for the project was calculated for a project length of 5 years, resulting in $991,888 NPV. The internal rate of return (IRR) was 120%, while the return on investment (ROI) was 22%. The discounted payback period (DPP) was 0.5 years. Total costs after reducing, mitigating, or controlling the IH hazards were $2,883,573.

Management also realized that their efforts to reduce employee exposures to air contaminants from metal removal fluids through a comprehensive MRF Control Plan needed to continue on a regular basis. The process is now institutionalized.

Lessons Learned

Without IH involvement in this problem, it would have been difficult to identify the source of the hazard because the relationship between illness and MRF is not well understood. With experience investigating complaints of this nature, IH was able to pinpoint the microbiological nature of the hazard and make recommendations that solved the problem.

Ultimately, the task force concluded that an effective MRF Management Program is essential for ensuring the health and safety of employees working in aluminum and iron metal machining operations. This was accomplished by developing a comprehensive MRF Control Plan that provided for proper selection of metal removal fluids, development of efficient coolant/machine maintenance schedules, and design of effective ventilation systems to maximize control of coolant aerosols. A multifunctional taskforce, including IH, was required to consider all aspects of S&H as well as manufacturing processes. The industrial hygienists played a key role in this task force.