Workers today are still being exposed to lead that result in adverse health effects. Recent studies have provided evidence that lead can cause health effects at blood lead levels lower than those established by OSHA’s 1978 Lead standard.
Epidemiological and experimental studies indicate that chronic exposure resulting in blood lead levels (BLL) as low as 10 µg/dL in adults are associated with impaired kidney function, high blood pressure, nervous system and neurobehavioral effects, cognitive dysfunction later in life, and subtle cognitive effects attributed to prenatal exposure. Pregnant women need to be especially concerned with reducing BLL since this can have serious impact on the developing fetus.
Chronic exposures leading to BLLs above 20 µg/dL can cause subclinical effects on cognitive functions as well as adverse effects on sperm/semen quality and delayed conception. BLLs between 20 to 40 µg/dL are associated with effects such as cognitive aging as well as deficits in visuomotor dexterity, lower reaction times and attention deficit. At BBLs above 40 µg/dL, workers begin to experience symptoms such as headache, fatigue, sleep disturbance, joint pain, myalgia, anorexia, and constipation.
While much less common today, workers can be exposed to high lead levels resulting in BLL over 60 µg/dL. Health effects at these very high BLLs can range from acute effects such as convulsions, coma, and in some cases, death, to more chronic conditions such as anemia, peripheral neuropathy, interstitial kidney fibrosis, and severe abdominal cramping.
OSHA’s general industry and construction lead standards include a medical removal protection provision for workers whose blood lead levels reach or exceed 50 µg/dL (construction) or 60 µg/dL (general industry) Recently, medical management guidelines for adult lead exposure has been developed by a national expert panel coordinated by the Association of Occupational and Environmental Clinics (AOEC), in collaboration with the NIOSH Adult Blood Lead Epidemiology and Surveillance (ABLES) program. The panel recommends that maintaining BLLs below 20 µg/dL over a twenty-year period, or below 10 µg/dL over a forty-year period, would be sufficient to prevent chronic effects associated with cumulative exposures.
Based on limited evidence of human carcinogenic effects, workers may develop stomach cancer and lung cancer following inhalation exposure to lead, but more studies are needed to demonstrate the cancer risks compared to the levels and durations of lead exposure, and possibly confounding factors such as smoking, diet, and other carcinogens in the workplace. Experimental research indicates that rats and mice develop renal tumors following exposure to lead.
The following webpages and publications provide additional information on the health effects of lead:
- Adult Blood Lead Epidemiology and Surveillance (ABLES). A long-standing state-based occupational health surveillance program of laboratory-reported adult blood lead levels (BLLs) conducted by NIOSH and 41 participating states.
- Medical management guidelines for lead-exposed adults:
- Association of Occupational and Environmental Clinics
- Council for State and Territorial Epidemiologists
- National Institute for Occupational Safety and Health (NIOSH) topics page on lead.
- Report on Carcinogens (RoC). US Department of Health and Human Services (DHHS), National Toxicology Program (NTP). Identifies and discusses agents, substances, mixtures, or exposure circumstances that may pose a health hazard due to their carcinogenicity. The listing of substances in the RoC only indicates a potential hazard and does not establish the exposure conditions that would pose cancer risks to individuals.
- Lead and Lead Compounds. NTP classification: Reasonably anticipated to be human carcinogens.
- NTP Monograph on Health Effects of Low-Level Lead
- International Agency for Research on Cancer (IARC) Monographs on the Evaluation of Carcinogenic Risks for Humans. World Health Organization (WHO). IARC Classification: Not classifiable as to its carcinogenicity to humans (Group 3).
- Toxicological Profile for Lead. Agency for Toxic Substances and Disease Registry (ATSDR). Includes links to information on health effects, chemical and physical information, potential for human exposure, and more.
- ToxFAQs™ for Lead. Agency for Toxic Substances and Disease Registry (ATSDR). Frequently asked health questions about lead.
- Case Studies in Environmental Medicine (CSEM): Lead Toxicity. Agency for Toxic Substance and Disease Registry (ATSDR).
- Lead. Environmental Protection Agency (EPA). Provides information on environmental lead poisoning and prevention for health professionals and the public at large.
- Lead Hotline - The National Lead Information Center. Provides information on lead exposure and related links to several US agencies, allowing the general public and professionals to find information about lead hazards and their prevention.
- EPA’s Integrated Science Assessment for Lead (2013). Provides the scientific bases for EPA’s decision regarding whether the current standards for lead sufficiently protect public health and the environment.
- Lead and compounds (inorganic) (CASRN 7439-92-1). Environmental Protection Agency (EPA), Integrated Risk Information System (IRIS). Contains information on health effects that may result from exposure to environmental contaminants.
- Lead Compounds. Environmental Protection Agency (EPA). Lists lead compounds as a Hazardous Air Pollutant (HAP) under the National Emissions Standard Hazardous Air Pollutants section of its Clean Air Act.
- Lead. New Jersey Department of Health and Senior Services, Hazardous Substance Fact Sheet. Provides a summary source of information of all potential and most severe health hazards that may result from lead exposure.
- International Chemical Safety Cards: Lead. National Institute for Occupational Safety and Health (NIOSH), (2002, August 10). Summarizes essential health and safety information on lead.
- HSDB. Hazardous Substances Data Bank. National Library of Medicine (NLM), Specialized Information Services (SIS). Provides access to a cluster of databases on toxicology, hazardous chemicals, and related areas.
- Elevated blood lead levels added to CDC’s List of Nationally Notifiable Non-Infectious Conditions, using the ABLES case definition.
- The Health Indicators Warehouse provides the current rate of elevated blood lead concentrations from work exposures among adults (per 100,000 employed persons aged 16 years and older).