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Nine of 10 Very High Blood Lead Levels Due to Occupational Exposure, Study Finds

Wednesday, December 4, 2013
By Robert Iafolla

Dec. 2 --Occupational exposure accounted for nine out of 10 cases of very high lead levels in the blood of adults tracked in a government study published Nov. 29.

Half of the 7,000 adults with very high blood lead levels--defined as 40 micrograms per deciliter--because of occupational exposure worked in manufacturing and a quarter were employed in construction, according to an analysis of data recorded by the Centers for Disease Control and Prevention's Adult Blood Lead Epidemiology and Surveillance program and published in the CDC's Morbidity and Mortality Weekly Report.

In particular, the study found that high levels of lead appeared among employees involved in battery manufacturing, painting and wall covering, nonferrous metal production and processing, and foundry work.

Overall, about 1 percent of the 1.2 million people who reported to the CDC's blood lead program had very high levels during 2002 to 2011. Forty-one states participated in the program. Researchers from the National Institute for Occupational Safety and Health led the study, which also drew on contributions from state health departments and academia.

Adverse Health Effects
Workers exposed to high lead levels can take the material home with them in their clothes and hair and expose family members--including children, who are particularly susceptible to health effects, according to Marie Sweeney, chief of NIOSH's surveillance branch and study co-author.

“There is a cascading effect with lead exposure,” Sweeney told Bloomberg BNA Dec. 2.

Research has found harmful health effects like decreased renal function and increased risk for hypertension among people with lead levels of less than 10 micrograms per deciliter of blood. People with very high blood lead levels for an extended period of time can experience spontaneous abortions, neurocognitive deficits, sperm abnormalities, anemia and kidney dysfunction, among other conditions.

The study found 2,200 adults experiencing very high blood lead levels for two or more years. Ninety-three percent of these persistent cases resulted from occupational exposure.

Control Measures Effective
Some of the workers in the study saw their high blood lead levels decrease sharply after the introduction of control measures such as personal protective equipment and mandatory showers.

“If we are willing to make changes, then workers will be affected,” said Walter A. Alarcon, NIOSH medical officer and also a study co-author. “Their blood lead levels will go down.”

Alarcon told Bloomberg BNA Dec. 2 that the onus is not only on employers to implement control measures, but also on workers to follow the measures and doctors to monitor and safeguard those who might be at risk.

Doctors have flexibility under the lead standard issued by the Labor Department's Occupational Safety and Health Administration to tailor measures to protect workers from lead to meet individual needs, the study said. The latitude doctors have includes the ability to remove workers from lead exposure at blood lead levels lower than the required thresholds in the standard.

Standard Seen as Part of the Problem
Still, the study suggested that the OSHA lead standard is a potential driver for high blood lead levels among workers because of its high thresholds. The standard calls for workers to be removed from the job if a construction worker's lead level reaches 50 micrograms per deciliter of blood or a general industry worker's level reaches 60 micrograms. Removed workers can return when lead levels fall below 40 micrograms.

Other possible triggers for persistent high levels include the failure of employers to implement engineering controls; workers not complying with safe practices; and state Adult Blood Lead Epidemiology and Surveillance programs not having the resources to investigate and refer to OSHA cases involving very high blood lead levels.

As of September, federal funding for state blood lead programs was discontinued. NIOSH's Alarcon said the funding cuts are expected to force state programs to stop their prevention activities, including contacting the employers of workers who test high for lead levels in their blood.

To contact the reporter on this story: Robert Iafolla in Washington at

To contact the editor responsible for this story: Jim Stimson at

Text of the study is available at

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