In a letter to a friend dated July 31, 1786, Benjamin Franklin wrote of lead's "mischievous" effects on workers. He cited his own encounters with the heavy metal 60 years earlier at a printing press and bemoaned how unsuspecting plumbers, painters and other professionals continued to be exposed and harmed.
"You will observe with concern," Franklin concluded the letter, "how long a useful truth be known, and exist, before it is generally received and practiced on."
Health experts echo Franklin's laments today. They say scores of working adults continue to be exposed to high levels of lead, including recent cases at indoor gun ranges, as regulations lag decades behind knowledge of the metal's health hazards and budget cuts further hamper efforts to prevent poisonings.
"The OSHA standard is so out of date, it's just ridiculous," said Howard Hu, dean of the University of Toronto Dalla Lana School of Public Health.
Hu referenced the U.S. Occupational Safety and Health Administration's current safety limit of 40 to 60 micrograms per deciliter of lead in a worker's blood, depending on the situation. Scientific studies have hinted that chronic blood lead levels as low as 2 micrograms per deciliter may raise the risk of death from a heart attack or stroke.
Evidence is also emerging of the role tiny amounts of lead may play in cognitive decline, reproductive disorders and kidney problems, along with other health issues common among Americans.
In fact, such research helped prompt the U.S. Centers for Disease Control and Prevention in 2009 to lower its threshold for an elevated blood lead level in adults from 25 to 10 micrograms per deciliter. Elevated levels in adults can cause adverse health effects, the CDC notes. The 10 micrograms figure is four times lower than the OSHA standard.
"We've made a lot of gains to-date -- we've got the lead out of gasoline, and out of paint -- but still more measures need to be taken," said Dr. Geoffrey Calvert, an occupational health researcher with the CDC.
Previous efforts often focused on protecting children, whose developing brains are particularly vulnerable to the heavy metal. The CDC even dropped its benchmark for kids to 5 micrograms of lead per deciliter of blood last year. But new research builds significantly on what was known in the 1700s, and even just five years ago: Lead poisoning can be a serious hazard for adults, too -- especially those working in areas like battery manufacturing, lead smelting, automobile repair, home renovation and gun ranges.
"Metals have been mined for 10,000 years, and the adverse effects of exposure is one of the oldest recognized occupational diseases," said Dr. Michael Kosnett, an occupational health expert at the University of Colorado, Denver. "There's clear evidence that levels currently tolerated in the workplace under OSHA standards constitute a risk to the health of workers."
Tony Myhre, a security guard in Everett, Wash., believes he is among many who've fallen victim to this discrepancy in what is considered an acceptable amount of poison.
"The numbers are confusing," he said. "Everyone is on a different page."
In late July, during a required training at an indoor gun range, he recalled becoming "tired and woozy." Gun ranges pose a threat due to lead dust released when firing leaded ammunition, and sometimes due to accumulated lead after years of bullets being fired in an enclosed space.
The night after the training, Myhre said, he suffered stomach cramps, a splitting headache and a persistent metal taste in his mouth. Instead of returning to the range the next day, Myhre went to his doctor.
A blood test revealed a lead concentration of 11 micrograms per deciliter, about 10 times the national average for adults. Myhre interpreted the result to mean he was lead poisoned -- exposed to enough of the element to make him sick and maybe even produce long-term consequences.
Brian Borgelt, manager of the Tacoma, Wash. gun range, had a different take.
"He was not lead poisoned. His lead level was below the standard trigger," he said, referencing the OSHA benchmark. Borgelt claimed no responsibility for any lead exposure, and said he wasn't concerned that Myhre may have suffered any significant damage to his health.
Since revising its definition of elevated blood lead, the CDC's Adult Blood Lead Epidemiology and Surveillance (ABLES) program has helped many states -- including Washington -- track workers like Myhre with blood lead levels as low as 10 micrograms per deciliter. While it's extremely unusual for such a level to be accompanied by symptoms, experts worry about the long-term effects.
"Ten micrograms should be reported so that we can see how many workers are at those dangerous levels, and implement interventions," said Dr. Walter Alarcon of the CDC's ABLES program.
But federal funding cuts threaten to stifle ABLES efforts. Todd Schoonover, an expert in occupational lead exposure with the Washington State Department of Labor and Industries, said his team is attempting to maintain their current program as long as possible, but Washington and other states may be forced to revert back to tracking only workers with levels above 25 micrograms per deciliter.
"It's gonna stink. There are plenty of populations of people for which exposure is ongoing and not being detected," said Hu. "The workers and their employers are simply ignorant of these kinds of exposures, the risks inherent in their work."
Mark Olson, an attorney representing a group of young men who allege they were lead poisoned while remodeling Wade's Eastside Guns in Bellevue, Wash., suggests there's another component to the problem beyond just ignorance: negligence.
Olson's son, Trevor, was one of those who say they were exposed to lead dust at the gun range last year. His blood lead level was in the upper-30s -- below the OSHA threshold, but enough to make him sick, Olson said.
"None of them were aware of the potential pitfalls of exposure to lead," said Olson of the workers. Olson alleged that Wade Gaughran, the owner of the gun shop and range, knew of the health hazards, "and sent these kids into harm's way."
Gaughran declined to comment.
Schoonover from the Washington State Department of Labor and Industries said ABLES information on Wade's Eastside Guns "really facilitated the quick and concerted action and intervention" when identifying the cases and preventing continued exposures. Washington is investigating the allegations, and the state's Department of Ecology is also looking into potential environmental damage due to lead, The Seattle Times reported.
ABLES is key, Schoonover said, to protect people.
"Could more things like this happen? Yeah. Could more fall under the radar? Yes," he said. "We need to reinstate funding." Schoonover noted that recent cases of lead exposure at gun ranges are bringing some fresh attention to an issue that is otherwise "not so sexy."
Unfortunately, the CDC is not the only agency facing financial constraints. OSHA spokesman Jesse Lawder acknowledged his agency's lead standard, set in 1978, lags behind the science.
"OSHA is not currently planning regulatory action to update the lead standard since available resources are committed to addressing other serious hazards, such as silica and beryllium," he wrote in an email statement to The Huffington Post. "We recognize that the blood-lead triggers are out of date, and recommend that employers go beyond compliance with OSHA standards and follow the CDC and other similar recommendations for exposure."
In California, where decisions to ban lead bullets and charge former lead paint manufacturers for threatening children's health are pending, state officials are taking it upon themselves to set more stringent occupational lead standards. Kosnett has served as a consultant in that effort.
"The process that's being undertaken in California, should it succeed, could be a model for the county," he said.
Deep budget cuts have also severed childhood lead poisoning prevention programs, just as expanding knowledge of adult health hazards hints at more threats to the next generation.
When a woman becomes pregnant, explained Hu, her bones begin dissolving to feed the demand of the fetus for crucial minerals. Research now suggests that lead stored in bone from earlier exposures can tag along, crossing the placenta and causing adverse effects.
Lead poisoning may also increase the risk of sterility in men, which is among the chief concerns of the young men who say they were exposed at Wade's. Some of the workers' kids are also suspected to have elevated lead levels in their blood due to the metal coming home on clothing and boots.
"One of the real pernicious effects of over-exposure to lead," Olson said, "is that these young men won't really know what the long-term consequences are until the long term."
CORRECTION: A previous version of this article misattributed comments made by Mark Olson about the lead levels in Trevor Olson's blood to Gaughran.