K2: Research Roundup Exposure Assessment/Laboratory Quality Assurance

On November 12th, 2024, the EPA published new lead dust clearance levels (DLCL) for HUD housing. This lowered the DLCL from 10 µg/ft2, 100 µg/ft2 and 400 µg/ft2 for floors, window sills, and window troughs to 5 µg/ft2, 40 µg/ft2, and 100 µg/ft2. The EPA also made two important changes to the LQSR (Laboratory Quality Assurance Requirements) which NLLAP accredited labs must follow to maintain endorsement. By December 22nd, 2025, labs must maintain a reporting limit that is 1.6-10 times the determined mdl (method detection limit). Labs are also required to reach a reporting limit no more than 80% of the lowest regulatory standards for DLAL's.

Flame Atomic Absorption Spectroscopy (FLAA) has been around commercially since the early 1960's and is the gold standard for lead dust wipe analysis. FLAA instrumentation is inexpensive, fast, robust, and reliable, that can produce accurate results for single elemental analysis. While Flame Atomic Absorption (FLAA) spectroscopy offers several advantages for lead dust wipe analysis it is not without its methodological and operational limitations. With EPA regulatory updates establishing that any quantifiable concentration of lead is considered hazardous, we are reaching the limitations of what FLAA can achieve. 

In IH Data Analyst software, championed by AIHA, workplace chemical exposures are analyzed using a Bayesian approach incorporating the prior knowledge that exposures usually follow a lognormal pattern. Studies with IHDA have led to the understanding that many IH practitioners who rely on traditional professional judgment (intuition), expect data to follow a Gaussian (normal) distribution which induces them to underestimate exposures. While AIHA has addressed this problem with free training programs, practitioners who do not embrace this new information continue to commit the fundamental errors arising from traditional IH education and training.

In much traditional IH training, since air sampling and analysis were seen as very expensive, a premium has been placed on making professional exposure judgments from a small number of samples; sometimes one or zero. This tradition was supported by OSHA's placing great emphasis on minimizing the error in sampling methods, while ignoring the large variation in workplace exposures, which led OSHA to believe they could detect worker overexposures by collecting small numbers of samples during rare workplace visits.

Recently, AIHA has urged employers to adopt a higher "Standard of Care" (beyond OSHA compliance) by utilizing the IH Data Analyst framework which allows one to ensure that the 95th percentile or worker exposures does not exceed the Occupational Exposure Limit (OEL).