Recreational shooters are carrying a lot of lead in their blood, analysis shows

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Wherever you stand on the question of whether it’s guns that kill people or people who kill people, you might be impressed by new findings about shooting ranges as a source of serious lead poisoning among their enthusiasts.

In occupational health and workplace safety circles it has long been recognized that police officers, soldiers and others who train intensively with firearms are exposed to lots of lead dust and fumes as they make holes in targets. Same for their trainers. There are workplace rules intended to limit that exposure and to monitor blood-lead levels for dangerous conditions.

What is newer is the expanding involvement of Americans in recreational shooting, as part of our ever-deepening love affair with guns in every form, and the lead-based risks this carries.

Private ranges aren’t subject to the same kinds of safety regulation as workplaces. Also, they attract a much higher proportion of women, for whom elevated blood levels are of greater concern (the same goes for children, whether young shooters or toddlers watching the grownups fire away).

How much lead are these nonprofessional range users taking in? Well, it varies a lot and is influenced by several factors:

Indoor ranges are worse than outdoor ranges because the dust and gases are confined. Blood-lead levels go up with the intensity and duration of shooting activity, of course. And there is some variation with gun type and caliber.

But here’s the key finding from a recent paper in the journal Environmental Health:

In a review of 36 studies from around the world, every single one found blood lead levels at roughly double the overall average of 1.2 micrograms per deciliter and usually above the 5 µg established as the official level of concern by the U.S. Centers for Disease Control and Prevention and the National Institute of Occupational Safety and Health.

Thirty-one of the 36 studies found BLLs above 10 µg, the level at which health professionals recommend reducing exposure (or in the case of pregnancy, impending pregnancy and certain medical conditions, halting exposure entirely).

Some very high levels

Half the studies found BLLs above 20µg, and 17 found them above 30 µg, at which point “prompt medical evaluation” is recommended. Fifteen found readings in excess of 40 µg.

The three dozen studies included both professional and recreational facilities worldwide and the new analysis did not attempt to distinguish them by BLL results. Rather, it makes the sensible and perhaps even obvious point that the health risks in both venues ought to be of equal concern and receive equal attention — but they don’t.

Drawing on industry statistics, the paper puts the number of shooting ranges in the United States at 16,000 to 18,000 as of 2013. It does not offer, and I could not find, a reliable breakdown as to how many of those are recreational, but a look at the listings maintained by the National Sport Shooting Foundation shows more than 350 in Minnesota and about 275 in Wisconsin, for two examples.

There is a breakdown of sorts for shooters, though: the paper says that about 1 million U.S. law enforcement officers train at indoor ranges, while 20 million citizens engage in target shooting as a leisure activity; as of 2011 there were about 270 million civilian-owned firearms in the U.S. compared to a global total of 650 million. And the owners practice a fair amount:

The National Sport Shooting Foundation (NSSF) stated that in 2011 in the United States there were 13,049,050 handgun shooters, 13,170,417 rifle shooters, 9,713,033 shotgun shooters, and 3,730,567 muzzleloader shooters who participated in 156,790,412 handgun shooting days, 146,652,398 rifle shooting days, 113,866,661 shotgun shooting days and 29,042,237 muzzleloader shooting days.

It’s not about the bullets

The late Daniel Patrick Moynihan once said, with memorable mockery, that “guns don’t kill people — bullets do.” But when it comes to poisoning people on the range, bullets and their fragments aren’t the biggest problem.

Most bullet projectiles  are made from lead, but a large amount of lead is also present in the primer, composed of approximately 35% lead styphnate and lead peroxide (and also contains barium and antimony compounds), that ignites in a firearm barrel to provide the propulsion for the projectile.

A portion of the lead bullet disintegrates into fine fragments while passing through the gun due to misalignments of the gun barrel. The lead particles, along with dust and fumes originating from the lead primer and the bullet fragments, are ejected at high pressures from the gun barrel, a large proportion of which occurs at right angles to the direction of fire in close proximity to the shooter. The shooter can inhale fine lead particulates (mainly from the primer) which constitutes the proximal exposure pathway.

Fine and coarse particulates from both the primer and bullet fragments also attach to the shooters’ hands, clothing, and other surfaces, and can be inadvertently ingested, less a source of elevated BLLs than the gases produced by explosion of the primer compound, providing another lead exposure pathway. When changing targets at outdoor firing ranges shooters can be exposed to lead that has accumulated in soil dust. Additionally, the shooters can then bring these particulates back to their home and expose their families as with other lead occupational hazards.

This also means, by the way, that long-gun shooters are exposed to more of the gases because they are ejected  nearer the face from a shouldered firearm than from a pistol held in the extended-arm stance.

The potential health impacts of the exposures found in this study are difficult to summarize because the toxic nature of lead is so complex — no level in the bloodstream can be considered completely safe, especially in children and pregnant women. And BLLs do decline over time, but in general they do so slowly without the assistance of chelation therapy, which carries its own medical downsides.

However, the paper lists some example health risks at different BLLs, drawing on a 2012 report from the U.S. National Toxicology Program, from the low end of the exposure spectrum:

5 µg: In children, “sufficient evidence” of decreased academic achievement, lowered intelligence quotient, increased attention-related behaviors, delayed puberty. In pregnant women, “sufficient evidence” of reduced fetal growth.

10 µg: In adults, “sufficient evidence” for hypertension, cardiovascular-related mortality, decreased kidney function; “limited evidence” of psychiatric effects, decreased hearing and cognitive function, incidence of amyotrophic  lateral sclerosis, increased spontaneous abortion. In children, hearing deficits.

Can’t get the lead out

There are good substitutes for lead ammunition, although as we are seeing this spring both in Congress and the Minnesota Legislature, there can be considerable resistance to requiring their wider use. Unfortunately, good substitutes are not yet available for lead-based primers, which themselves were developed to replace another toxic product:

During the 19th century primers were composed of mercury fulminate; however, the mercury fulminate was found to be too toxic to shooters. In the early 20th century, Dynamit Nobel developed the primer SINOXID which was formulated with lead and became a universal primer.

By “… the 1960s exposure of shooters and firing range supervisors to lead reached intolerably high levels, as evidenced by the elevated blood lead values.” Dynamit Nobel developed SINTOX, a lead-free (as well as antimony- and barium-free) primer.

 However, the results of some tests of the lead-free primers have proven disappointing, with significant variations in ignition timing, peak blast pressure, higher barrel frictions, and reliability in different climate conditions, compared with their lead-based equivalents. The performance of lead-free primers is being tested by the U.S. Department of Defense and North Atlantic Treaty Organization to reduce exposure of personnel to known lead sources.

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The full paper by Mark A.S. Laidlaw, an epidemiologist from Indiana University-Purdue University at Indianapolis who is now a postdoctoral fellow at the Royal Melbourne Institute of Technology in Australia, can be read here without charge.