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workers, building, architect

NORA Manufacturing Sector Strategic Goals

927ZGNX - Quality Assurance Techniques for Laboratory Liquid Aerosols

Start Date: 10/1/2008
End Date: 9/30/2011

Principal Investigator (PI)
Name: Robert Glaser
Phone: 513-841-4270
Organization: NIOSH
Sub-Unit: DART
Funded By: NIOSH

Primary Goal Addressed

Secondary Goal Addressed

Attributed to Manufacturing


Project Description

Short Summary

This project addresses the goals of reducing respiratory disease primarily in the manufacturing sector. More accurate estimates of exposure dosage are needed to protect an estimated 2 million US workers exposed to MWF from occupational asthma, hyper-sensitivity pneumonitis, and possibly cancer. Such dosages are routinely underestimated due to significant evaporation of condensed aerosol and/or loss of vapor phase components of a MWF sample using filter-only sampling or during storage and shipment of samples. A novel device that uses a filter to sample the MWF aerosol components and a high-capacity low pressure drop sorbent bed to sample all volatile contaminants has been designed. Performance tests of this sampler for analysis of liquid aerosols with partner laboratories will assure the public that NIOSH meets the quality and transparency criteria of the 2001 Data Quality Act.


There are approximately 2 million workers in the United States exposed to MWF; such exposures can result in occupational asthma, hypersensitivity pneumonitis and possibly cancer. Current sampling and analytical techniques underestimate or ignore the nonvolatile and volatile MWF aerosol components and vapor-phase contaminants of the work environment. In order to truly estimate worker dosage due to inhaled MWF, a robust technique is needed which samples all of the workplace contaminants. It is also essential that the developed analytical procedure meet the stringent requirements of the Data Quality Act (DQA) of 2001. This project aims to develop needed analytical methodology for MWF and to study the performance of that methodology among multiple laboratories such that data obtained using that methodology meets the quality and transparency criteria of the DQA. Successful performance testing of the method, conducted in accord with ASTM requirements, will provide significant support for national and international usage of the technology. This performance testing will also be used to provide participants with feedback to non-conforming laboratories so that corrective action may be taken. Pending outcome of the performance testing, the technology developed may be transferred to an NGO such as AIHA for implementation of routine liquid aerosol performance testing as part of its overall proficiency testing program. The analytical method(s) will be published for field usage in NMAM and the results of the performance studies in the relevant industrial hygiene literature. As this project addresses these needs, it supports Goal 2.3 of the Exposure Assessment Coordinated Emphasis Area which calls for improved methods for assessing environmental exposure to workplace chemicals. This should significantly improve the understanding of occupational risks involved in use of MWF. Use of these methods should make it possible to reduce the incidence and severity of respiratory effects of inhaled MWF, thus addressing the Respiratory Disease Strategic Goal 1 to prevent and reduce work-related airways disease and respiratory malignancies.


An informal survey of industrial hygiene equipment suppliers and AIHA accredited laboratories could be conducted to substantiate the magnitude of the use the new sampling device by industrial hygienists and analytical methods by laboratories for the assessment of MWF workers' exposures.

Mission Relevance

There are approximately 2 million workers exposed to metalworking Fluids (MWF) in the United States. Metalworking fluids (MWFs) lubricate, cool, and remove debris from the work surfaces of metal parts that are being drilled, ground, milled, or turned. They are generally classified according to the amount of mineral oil that they contain. Straight fluids primarily contain mineral oil. The three other types of MWF are all mixed with water prior to use. They include soluble fluids that contain up to 80% mineral oil, semisynthetic fluids that contain up to 40% mineral oil, and synthetic fluids that contain no mineral oil. Water-mixed fluids may also contain alkanolamines, biocides, boron compounds, and emulsifiers as well as ionic and nonionic surfactants.

During use, MWF form liquid and semisolid aerosols that are significant inhalation hazards that likely contribute to occupational asthma, hypersensitivity pneumonitis, and possibly cancer. In 2005, ASTM released Method ASTM Method D-7049-04 for metalworking fluids. This permits separation of MWF from co-sampled solid particulate using a solvent elution scheme. NIOSH has released its own version of this technique as Method 5524. The sampling and analytical method(s) have been used to support a NIOSH survey of 79 metalworking facilities across the United States, and 21 NIOSH surveys of MWF exposures in machining operations. It is estimated that at least 2000 samples have been analyzed at NIOSH using NIOSH Method 5524. Recently, the NIOSH/ASTM methods were adopted by and incorporated into the French Institut National de Recherche et de Sécurité (INRS) methods manual. Thus far, only one performance-test of the method has been completed and that only for a single semisynthetic fluid. Although the method performed well in that test, one laboratory did produce results that were statistically less precise and biased low relative to seven other labs.

The filter-only technique of method 5524 does not account for evaporation of condensed MWF aerosol and/or loss of vapor phase components during sampling. This may be a significant problem, especially for straight fluids. NIOSH has likely been reporting MWF sample concentrations that understate the true level of worker exposure to MWF aerosol by ignoring the volatile aerosol and vapor components of the MWF exposure. It is an objective of this project to develop a sampler which traps the aerosol on a filter and the volatile atmosphere components on a sorbent.

Another objective of this project is to assure that analytical method(s) for such MWF aerosols developed with this sampler meet the quality and transparency criteria of the Data Quality Act. Liquid aerosols present a continuing sampling and analytical challenge and a proficiency testing program is needed to assure the quality of results from laboratories analyzing them. Aerosolized QA MWF samples should be supplied to such labs as a routine part of a certification program by an appropriate proficiency testing organization. Such an organization is likely to require that the sampling and analytical method be validated according to the guidelines of an independent evaluating body (e.g., ASTM). In its guidelines for validation of analytical methods, ASTM states "whenever feasible, an interlaboratory study must be conducted. This procedure will provide specific estimates of variation anticipated when using the test method". Thus, a large scale multi-lab performance test of the device using samples of synthetically-generated MWF aerosols must be conducted before any certification organization is likely to consider incorporating liquid aerosol samples into a proficiency program. This project addresses the NORA goals to improve exposure assessment techniques for workplace chemicals.