A significant percentage of workers tested for blood lead continues to show elevated levels, the Occupational Health Branch (OHB) says in a report by its Occupational Lead Poisoning Prevention Program.
The findings come as OHB is finalizing scientific work that will be the basis for its recommendation on blood lead levels to the Division of Occupational Safety and Health. The branch, part of the California Department of Public Health, expects to announce its findings this fall.
OLPPP conducts yearly surveys of blood lead based on samples it collects from adults older than 16 years. The test results are entered into the California Occupational Blood Lead Registry. CDPH uses the data to identify cases of lead poisoning requiring follow-up and to target employers and industries for prevention efforts.
Health authorities recommend that blood lead levels (BLLs) be maintained below 10 micrograms per deciliter to prevent such long-term effects as hypertension, and decreases in kidney and cognitive function. Current Cal/OSHA requirements in Construction Safety Orders §1532.1 and General Industry Safety Orders §5198 set a permissible exposure limit of 50 µg/dl.
A DOSH draft proposal would require medical surveillance of workers every three months when they show a BLL between 10 µg/dl and 20 µg/dl, and medical removal for workers with levels above 30 µg/dl. They could be returned to the previous job status only when their BLL is at or below 15 µg/dl for two consecutive tests. The proposal is controversial among some stakeholders.
The OLPPP report notes that it is difficult to “fully describe the magnitude and distribution” of elevated BLLs in California because many employers don’t test their lead-exposed workers at all. The data in the survey “likely represent a significant underestimate of the number of workers in California overexposed to lead.”
Every year, OLPPP receives more than 56,000 reports, representing about 50,000 individuals. Among those, about 2,000 are considered non-occupational exposures, about 18,000 are occupational exposures and around 30,000 are unknown as to the source of the exposure. (Some workers are tested more than once, so the totals often don’t match.)
The yearly reports show that of the workers tested, between 8% and 10% show BLLs at or greater than 10 µg/dl. The total number of workers with elevated BLLs between 2008 and 2011 was 3,615. The numbers in the accompanying chart are higher because some workers were tested multiple times within a year.
The report shows that up to 97% of the workers with elevated BLLs are male and 88% are between 20 and 59 years old. Hispanic/Latino workers had a disproportionate share of the elevated levels. They represented 36% of the workforce in 2011, but had 64% to 70% of the high BLLs, “suggesting that Hispanic workers are more likely to be exposed to lead on the job,” CDPH.
Almost half of the workers with high BLLs worked in Los Angeles County (44%-49%), followed by Riverside County (7%-9%.)
CDPH notes that individuals reporting to the registry worked in more than 200 industries, but just a few sectors accounted for the largest number of workers receiving tests, including:
Remediation services, particularly lead abatement
Storage battery manufacturing
Site preparation, primarily wrecking and demolition
Government air, water and waste programs
Secondary smelting, primarily battery recycling
Scrap metal and electronic recycling
Of the workers showing elevated BLLs, 58% worked in manufacturing, 17% in construction and 23% in other industries.
CDPH concludes, “It is clear that many employers who test have been successful in controlling lead exposure.”
OLB is making final changes to the scientific model that has been developed by Cal/EPA’s Office of Environmental Health Hazard Assessment to explain the relationship between exposure levels to blood lead, and form a sound scientific basis for OHB to recommend a PEL to Cal/OSHA. “They do not expect to go through another round of peer review,” says Deborah Gold, DOSH Deputy Chief for Health and Technical Services. The final report will recommend the PEL and CDPH hopes to hold a scientific meeting this fall to discuss the report, its methodology and recommendations. “After that, the Division will hold an advisory meeting to suggest the recommended changes to the standards,” Gold says.
Click here to see a full copy of the OLPPP report.