NIOSH Investigates Dermatitis among Rifle Barrel Manufacturing Employees

Published July 12, 2017

​Staff from NIOSH’s Health Hazard Evaluation (HHE) Program recently responded to a manager’s concerns about skin irritation and rashes among employees who were exposed to metalworking fluids (MWFs) at a rifle barrel manufacturing company. Some production employees also reported work-related asthma-like symptoms. The facility mainly used two types of MWFs: a mineral oil-based MWF they refer to as “oil” and a semisynthetic water-based MWF they refer to as “coolant.” According to NIOSH, dermal contact with MWFs may cause skin disorders, and inhalation of MWF aerosols may irritate the throat, nose, and lungs. NIOSH staff visited the facility twice to observe work practices and personal protective equipment use; review illness and injury logs, workers’ compensation claims, and air sampling reports; interview employees; and examine employees’ rashes. They also took personal air samples for MWF mist and endotoxin, a compound released from certain bacteria when they die or multiply and is believed to cause respiratory illness. The agency found that many employees had skin exposure to MWFs, including oils and coolant, and to rust inhibitor, with the highest MWF mist levels occurring in the milling and chambering departments. Prior to the NIOSH evaluation, the plant had reduced production levels and made other changes that reduced the risk of dermatitis from oil-based MWFs, including switching to a different oil and improving exposure controls, training, work practices, and hygiene. However, agency staff found a “significant association” between skin exposure to coolant and work-related dermatitis at the facility, with co-exposure to the corrosion inhibitor as a potential “important contributing factor.”

“Employees with work-related respiratory symptoms were exposed to airborne MWF levels that have been known to cause or exacerbate respiratory symptoms, although the exposures are at or below NIOSH-recommended limits,” the agency report continues. “Actions are needed to protect employees from developing or exacerbating dermal and respiratory problems related to MWF and other chemical exposures in the plant.”

NIOSH recommends limiting employees’ skin and respiratory exposures to MWFs by improving MWF mist control, changing manual handling practices, and improving employees’ access to and consistent use of gloves. The employer should also encourage employees to report potential work-related symptoms early to help prevent more serious problems.

Further details and recommendations from the NIOSH evaluation are available in an HHE report (PDF).