It’s easy to see why this heavy metal is abundant in industry. Lead is durable, resists corrosion, shields radiation, melts at a relatively low temperature, can be easily recaptured with recycling, and makes paints brighter and long-lasting. OEHS professionals need to understand that regulatory authorities across the United States are changing their requirements for lead, and that community exposures may affect the workforce as well.

HEALTH EFFECTS Lead is a true poison in that it has no use in the body. But because it mimics calcium very well, it can easily find its way into many systems. While most people correlate calcium with “bones,” the bigger concern is neurons and blood vessels.

In the brain, calcium is an essential player in how neurons communicate to each other via neurotransmitters. When lead clogs up the area where calcium should be received, neurons communicate with each other inappropriately, potentially affecting memory and learning. The Cincinnati Lead Study found that children exposed to lead had damage to the pre-frontal cortex. This area of the brain, which matures around age 25, is responsible for attention, complex decision making, and behavior regulation. When lead reaches blood vessels, it continues to mimic calcium. In a healthy body, calcium promotes vessel narrowing to increase blood pressure, but lead damages vessels over time and causes cardiovascular disease. Exposure to lead can put a person at risk for heart attack, stroke, or other complications.

While most adults don’t feel ill after an exposure, symptoms can include headache, cramps, nausea, muscle pain or stiffness, loss of sex drive, irritability, fatigue, or trouble sleeping. Exposure to lead is associated with adverse health effects including but not limited to the reproductive, cardiovascular, neurological, respiratory, and immune systems. Lead is also ototoxic.

Geologically speaking, lead comes from galena mines. In 2022, according to Mining Technology, the U.S. was the world’s third largest producer of lead, with the largest domestic mines located in Alaska, Missouri, and Idaho. Once it is mined from the earth, the ore is smelted down to extract the lead and, often, the associated silver. Anything the ore touches should be considered suspect for contamination until tested otherwise. Workers in the downstream process who are responsible for cleaning containers need to know their potential exposure.

As our technology changes, a large amount of our market lead is coming from recycled sources. Lead has a surprisingly high recapture rate, and the U.S. has a robust recycling program for lead acid batteries such as those found in automobiles, electric wheelchairs, and forklifts. While other types of batteries like lithium ion or lithium titanate are established in many processes, lead acid batteries are still a global standard. Recycling the batteries involves breaking them apart and soaking them in water, where the heavy lead sinks to the bottom while the plastic waste floats to the top. The battery acid is treated, and the lead is turned into recycled ingot.

Lead has long been put into products that are part of industrial processes. The history of lead in the U.S. includes milestones related to workers’ exposures. For instance, regular gasoline has not included lead since 1975, and gas became completely lead free for on-road vehicles in 1986. A federal ban on lead-based paint was instituted in 1978, but many cities and states had acted earlier. In 1951, Baltimore became the first city in the U.S. to ban the use of lead-based paint in residential homes, with New York City following in 1960.

While lead isn’t currently used in piping and soldering, it has a long history in plumbing. In fact, the Latin word for lead, plumbum, is the root of both “plumbing” and the elemental symbol for lead, Pb. Lead solder was widely used to join copper pipes until 1986, when a rule was passed to ban this practice. According to a recent EPA report, approximately 9 percent of residential homes are serviced by lead pipes with the highest concentrations in Florida, Illinois, Ohio, Pennsylvania, Texas, and New York. While this statistic doesn’t capture pipes to commercial or industrial spaces, it does illustrate an exposure to residential contractors who service these homes. Any workers who interact with buildings that have old paints and piping should be aware of where lead hazards are found. Affected industries include not only lead abatement work, but range from commercial to residential, and repair to demolition.

Shipbreaking is notorious for its frequent lead exposures. OSHA’s National Emphasis Program for shipbreaking, which went into effect in 2016, specifically references lead exposures. In the maritime industry generally, lead-based paints are used in vessels because of their anti-corrosive properties. Lead can also be found in greases, in fuel additives, and as radiation shielding on nuclear vessels. Maintenance and abatement efforts on vessels can lead to higher-than-average exposures not only because marine paints have higher concentrations of lead by volume but because vessels and docks have many confined or enclosed spaces where airborne particulates can concentrate. In these spaces, ventilation and personal protective equipment can be cumbersome at best.

In recent years, the telecom industry and firing ranges have gotten attention for their lead exposures. Telephone lines installed before 1960 have lead in the sheath to protect the copper wires from electromagnetic interference. While most of these legacy lines don’t go into homes or buildings, they serve as the infrastructure cables hooked up to a pole or buried underground, and they still pose an exposure risk to utility workers coast to coast who need to update or repair utility infrastructure. The Wall Street Journal has published multiple stories on lead in the telecom industry, including a recent piece on workers affected by their exposure to this heavy metal. Workers in firing ranges, especially indoor facilities, and construction workers who may be renovating them have potentially high exposures. An article from National Public Radio in 2017 that reviewed OSHA data and workers’ exposures from multiple states revealed that of the 350 air samples taken over 30 years, almost half exceeded the current PEL of 50 µg/m3 averaged over an 8-hour period. Workers can be exposed from the ammunition itself, which contains lead, and from lead contamination: bullets are typically stopped in a sand berm, hands that touch the ammunition and firearm are contaminated until properly washed, and specialized ventilation is needed that must be properly maintained because lead is aerosolized in the firing range.

FEDERAL AND STATE REGULATIONS OSHA has begun rulemaking to revise standards for occupational exposure to lead. This action was motivated in part by research indicating that health effects can occur in adults at a much lower blood lead level (BLL) than previously thought and that the current PEL is not protective. The revised rule could affect areas in the code such as BLL triggers for medical removal protection (MRP); medical surveillance provisions, including triggers and frequency of blood lead monitoring; the PEL; and ancillary provisions for personal protective equipment, housekeeping, hygiene, and training.

The OSHA lead standard for general industry and maritime (29 Code of Federal Regulations 1910.1025) was promulgated in 1978, and the lead standard for construction (29 CFR 1926.62) was established in 1993. Currently, OSHA medical removal limits are triggered when workers receive a BLL test at or above 60 µg/dL in general industry or 50 µg/dL in construction; they can return to work when their BLL is less than 40 µg/dL. These triggers may change under OSHA’s new rulemaking. However, a few states are moving forward before OSHA, giving OEHS professionals and other interested parties an idea of where federal guidance may land.

California California published a notice of intent in March 2023 to change its lead rule. The notice includes trigger tasks and altered definitions that are important to note, especially for OEHS professionals working in the state. Some of the larger reductions include:

• the intent to maintain employee BLLs below 10 μg/dL, four times lower than existing regulations, which were designed to maintain employee BLLs below 40 μg/dL

• lowering the action level, which triggers certain required protective measures, from 30 μg/m3 as an 8-hour TWA to 2 μg/m3 as an 8-hour TWA

• lowering the PEL for lead, calculated as an 8-hour TWA, from 50 μg/m3 to 10 μg/m3

The notice also includes multiple changes regarding workers’ BLLs. It lowers the BLL at which specified employees must be offered medical examinations and consultations at least annually from 40 μg/dL to 20 μg/dL. It lowers the MRP criteria from 50 μg/dL to one BLL at or above 30 μg/dL. As written, one year after the rule goes into effect, MRP will be triggered when a worker’s last two BLLs are at or above 20 μg/dL or the average of all BLLs in the last 6 months is at or above 20 μg/dL. The California notice also lowers the BLL that employees must achieve before returning from MRP to work involving lead from 40 μg/dL to 15 μg/dL.

Washington Washington state also has rulemaking movement on its website. The most recent draft, dated June 2019, has a proposed airborne PEL of 20 μg/m³ (8-hour TWA), and, like California, a goal of keeping workers’ BLLs at 10 μg/dL. If a worker is exposed over the PEL or has an elevated BLL, the workplace needs to implement exposure controls. Also similar to California, Washington’s draft rule has language focused on workers’ BLLs (see Table 1).

BEING INDUSTRIAL LEAD-ERS OF THE COMMUNITY The impact of these new workplace protections will be life altering. But in the midst of these changes, reducing exposures to industrial contaminants that can be found in the community and home environment takes on an elevated level of importance. Lead exposures and their health effects are in direct opposition to a worker’s social determinant of health. If workers live in a community where they may be exposed to failing infrastructure, this creates a possibly compounding health concern, potentially elevating their BLL and emphasizing the importance of lowering workplace exposures where industry may have more readily available resources. News coverage of workers who are exposed to lead indicates that their biggest concerns include the potential exposure of take-home lead to their children. When our workers have community exposures due to older housing, contaminated outdoor spaces, or failing infrastructure, we have the opportunity to advocate for lead safety because outside exposures affect workplace exposures as well.

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