Metalworking Fluid Mist Occupational Exposure Limits: A Discussion of Alternative Methods

Abstract

NIOSH published a recommended exposure limit (REL) for metalworking fluids (MWF) in 1998 that was designed to prevent respiratory disorders associated with these industrial lubricants. The REL of 0.4 mg/m(3) (as a time-weighted average for up to 10 hours) was for the fraction of aerosol corresponding to deposition in the thoracic region of the lungs. This nonregulatory occupational exposure limit (OEL) corresponded to approximately 0.5 mg/m(3) for total particulate mass. Although this REL was designed to prevent respiratory disorders from MWF exposures, NIOSH acknowledged that exposures below the REL may still result in occupational asthma and hypersensitivity pneumonitis--two of the most significant respiratory illnesses associated with MWF. In the 8 years since the publication of the NIOSH MWF REL, neither the Occupational Safety and Health Administration (OSHA) nor the American Conference of Governmental Industrial Hygienists (ACGIH) has recommended an exposure limit for water-soluble MWF specifically, other than their previous exposure limits for mineral oil. An informal effort to benchmark companies involved in the manufacture of automobiles and automotive parts in North America indicated that most companies are using the NIOSH MWF REL as a guide for the purchase of new equipment. Furthermore, most companies have adopted a goal to limit exposures to below 1.0 mg/m3. We failed to find any company that has strictly enforced an OEL of 1.0 mg/m(3) through the use of either administrative controls or personal protective equipment, when engineering controls failed to bring the exposures to below this limit. We also found that most companies have failed to implement specific medical surveillance programs for those employees exposed to MWF mist above 1.0 mg/m(3). Organization Resources Counselors (ORC) published in 1999 (on their website) a "best practices" manual for maintaining MWF systems and reducing the likelihood of MWF-related illnesses. The emphasis of this approach was on control techniques, and there was no assignment of a specific OEL for MWF due to the wide variety of fluids that exist. The ORC did suggest that maintaining exposure levels to below 2.0 mg/m(3) would assist in minimizing upper respiratory complaints associated with MWF. Although the ORC manual indicated that MWF vary in composition and no single OEL is likely to be appropriate for all such fluids, it adopted a very similar concept to control banding, placing all MWF operations into a single band using similar (if not identical) controls. OSHA, in lieu of adopting a 6B health standard for MWF, has also published a voluntary "best practices" manual on their website. Their document drew heavily from the work of ORC and also incorporated information from the 1998 NIOSH MWF criteria document. Industrial users of MWF need to have guidance, such as an OEL, to determine when either engineering, administrative controls, or personal protective equipment must be implemented to protect their employees. The purpose of this article is to explore various...

Microorganisms in metalworking fluids: Current issues in research and management

“…In the European Union, the regulations regarding the permissible level of microbial contamination in MWFs have not been yet established. Also, a consensus on research techniques and the rational principles of microbiological monitoring of MWF's installations has not yet been reached [1,4]. The scarce data, accessible in the literature are difficult to interpret because different analytical procedures and sampling techniques of MWFs are used in the individual EU countries.…”

Human Health Concenrs of Metalworking Fluid Components

“…The hazards of any substance can be generally considered as a product of its inherent toxicity and the exposure or dose that a worker receives. More subtle issues may enhance the hazard, such as individual susceptibility to a specific agent or illness (12). Because of adverse effects on human health of some substances, the issue of additives has changed during the decades.…”

Hypersensitivity pneumonitis and metalworking fluids contaminated by mycobacteria

“…At the time of writing, 12 clustered cases have been described in Europe, in the UK [26], and ,100 cases in USA [2,3]. The National Institute of Occupational Safety and Health (NIOSH) published a recommended exposure limit (REL) for MWF in 1998 to prevent respiratory disorders associated with industrial lubricants [37]. The REL is 0.4 mg?m -3 [37].…”

“…The National Institute of Occupational Safety and Health (NIOSH) published a recommended exposure limit (REL) for MWF in 1998 to prevent respiratory disorders associated with industrial lubricants [37]. The REL is 0.4 mg?m -3 [37]. COHEN et al [37] recently suggested that manufacturing companies failed to control the level of exposure to ,1 mg?m -3 and that protective equipment or medical surveillance programmes are insufficient.…”

“…The REL is 0.4 mg?m -3 [37]. COHEN et al [37] recently suggested that manufacturing companies failed to control the level of exposure to ,1 mg?m -3 and that protective equipment or medical surveillance programmes are insufficient. GUPTA and ROSENMAN [38] point out that HP arose from environments with exposures well below the Occupational Safety and Health Administration (OSHA) permissible exposure limit for MWF and, in one case, from exposures well below the NIOSH REL.…”