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The Qualitative Fit Test (QLFT) is a widely used method to assess the effectiveness of respiratory protection devices, particularly in occupational settings where hazardous airborne contaminants are present. Unlike Quantitative Fit Testing (QNFT), which provides a numerical measure known as the fit factor, QLFT relies on the subjective responses of the wearer to detect the presence of a test agent. Despite its widespread use, QLFT has inherent limitations that may prevent it from ensuring a fit factor of ≥100, the quantitative level required for half mask respirators.
The reliance on sensory detection in QLFT introduces variability due to individual differences in sensitivity to the test agent or possible deception by the subjects. This subjectivity can lead to false negatives, where a respirator may be deemed adequately fitting when, in fact, it does not provide the required level of protection. Additionally, following correct donning and doffing procedures significantly impacts the fit quality. Furthermore, QLFT is often conducted under controlled conditions that do not replicate the range of movements and environmental factors present in real-world settings, further limiting its accuracy.
This presentation explores the critical factors contributing to the discrepancy between QLFT results and achieving a fit factor ≥100. It discusses the implications of various procedures within the QLFT protocols that potentially create bias and waste time. We propose pursuit of an improved QLFT protocol to enhance the reliability of fit testing outcomes and save employer resources. Addressing these limitations is crucial for ensuring that workers are adequately protected in environments where respiratory hazards are present 

The NIOSH Health Hazard Evaluation (HHE) Program helps employees, unions, and employers throughout the United States by evaluating health and safety in a diverse set of workplaces. During this session, we will discuss recent interesting HHEs that NIOSH teams have completed. We will present methods, findings, and recommendations from evaluations of 1) lead exposure during bullet recycling, 2) noise exposure in a clinical laboratory, and 3) illicit drug exposures to forensic scientists in a toxicology lab. The first HHE was requested by a lead bullet recycling company's management to evaluate lead exposure among employees processing lead-containing bullets. The request occurred after the New Jersey Department of Health identified a group of employees with high blood lead levels (above 40 micrograms per deciliter). We found that most of the employees were overexposed to lead in air, lead was detected on nonproduction surfaces and inside employees' protective gear, and employee blood lead levels were elevated. The second HHE, a state government laboratory employer representative request, evaluated employee noise exposure from instruments and equipment in newborn screening and microbiology laboratories and from the ventilation system in the molecular laboratories. The noise levels measured were below the Occupational Safety and Health Administration and NIOSH occupational noise exposure limits and are not considered to present a risk of hearing loss. However, the noise levels were high enough to potentially interfere with employee communication and speech recognition. The third HHE was an employer representative request at a state police agency concerned about potential occupational exposure to illicit drugs, among employees working in a toxicology lab. Detectable levels of methamphetamine and cocaine were found on some surfaces. One of the surface samples exceeded the state limit for methamphetamine contamination (1.5 micrograms per 100 square centimeters) in remediated spaces. NIOSH made recommendations in all three workplaces following the hierarchy of controls (engineering, administrative, and personal protective equipment) to protect the bullet recycling, scientists, and laboratory employees from hazardous occupational exposures. 

In the late 1970's the extensive use of organophosphate, N-methyl carbamate and chlorinated hydrocarbon pesticides in agriculture was a matter of concern for the health and safety of persons engaged in high contact cultural practices (e.g., cane turning and thinning in grapes) and during harvest. As part of their daily employment workers were in situations of constant potential exposure to pesticide residues on foliage. Such low-level exposure, though believed to be negligibly hazardous, still needed to be quantified to understand the background exposure of fieldworkers.

One method for understanding and measuring potential pesticide exposure involved collecting foliar samples and comparing the residue levels found on the leaves with estimated "safe levels" developed by toxicologists. Only the residue that could transfer to the worker was considered hazardous, since embedded residue was bound up in the leaf itself and not available for transfer. Thousands of samples were taken in the 80's and 90's to characterize exposure. However this database has become somewhat obsolete, since many of the pesticides used back then are no longer available now. The Worker Health and Safety Branch of the California Department of Pesticide Regulation decided to reinstitute the Dislodgeable Foliar Residue Project to get a more contemporary understanding of the residues workers were now being exposed to.