What’s really behind the controversy over use of traditional lead based ammunition? Is the debate a Trojan Horse strategy aimed at banning all hunting in the United States? Or is it simply concern about a preventable cause of wildlife mortality?

If the Humane Society of the United States has its way, use of traditional lead ammunition will be barred from all public lands. The group recently filed a petition with the Department of the Interior to completely ban use of lead ammunition on public lands, which comprise about one-fifth of all territory in the country.

A clue to the group’s motives may be found from Humane Society leader Wayne Pacelle, who stated in a 1990 interview with Full Cry magazine that his mission was to ban hunting nationwide.

“We are going to use the ballot box and the democratic process to stop all hunting in the United States,” he said. “We will take it species by species until all hunting is stopped in California. Then we will take it state by state.”

Partly as a result of the Human Society’s efforts, the California senate passed Assembly Bill 711, which implements a ban on lead ammunition in the state effective in 2019. In a National Shooting Sports Foundation article, the organization’s chief Larry Keane expressed concern that the bill creates a de facto hunting ban.

“Proponents misleadingly claim alternative hunting ammunition will be readily available,”he said. “What will be available is substantially more expensive than traditional ammunition.”

Keane also points out the potential impact on wildlife conservation funding in the state.

“In 2012, California received more than $12 million in Pittman Robertson funds, ranking it one of the top five state beneficiaries,”he added. “The very ammunition the bill’s proponents demonize is what pays for wildlife and habitat conservation.”

But according to the Humane Society, upwards of 20 million animals die each year from lead poisoning in the United States.

“Up and down the food chain, animals are faced with varying degrees of risk for exposure to toxic lead ammunition, including mice, squirrels; frogs; ducks; swans; bald eagles; deer; grizzly bears and yes, even humans,”it said.

Human Society Campaign Manager for Lead-Free Wildlife Michelle McDonald points to a past success.

“Hunting lobby groups who oppose a move away from lead in ammunition are the same groups that opposed the phase-out of lead shot for waterfowl hunting in 1991 — which is considered one of the greatest conservation successes of the past century,” she explained.

McDonald also argues that hunting activity is not under attack.

“These groups said at the time that it would be the end of duck hunting and goose hunting in America, and their claims have been proven false,” she said. “Today waterfowl populations are strong, many fewer millions of animals die from lead poisoning, and non-lead shot is more affordable and readily available than ever before.”

“Phasing out this notorious toxin out of hunting ammunition doesn’t take away a single acre of land, a single day of hunting, or a single species for hunters, but simply stops the poisoning of land and animals,” McDonald added.

The National Shooting Sports Foundation is not convinced that there is ample scientific evidence to support sweeping policy or legislation.

“The NSSF opposes efforts to ban or restrict the use of traditional ammunition containing lead components for use in hunting or shooting unless there is sound science conclusively establishing that the use of traditional ammunition is causing an adverse impact on a wildlife population, the environment or on the human health of those consuming game harvested with traditional ammunition, and that other reasonable measures, short of restricting or banning the product, cannot be undertaken to adequately address the concern,”the industry lobby group said.

Caught in the middle is the United States Department of the Interior, which declined comment on the petition forwarded by the Humane Society.

“We have received the petition and are reviewing its contents,” said Interior spokesperson Jessica Kershaw.

According to the NSSF, a premature policy or legislative decision could destroy not only an activity enjoyed by millions of Americans, but cause untold negative economic and environmental impact from disruption of the $48 billion hunting industry.

Excise taxes of 11 percent on every dollar of ammunition produced are the primary source of conservation funding designed to protect the very populations at issue. For example, hunters using traditional ammunition primarily funded the recovery of the Bald Eagle. If rash decisions are made that impact the volume of ammunition purchases and hunting activity, it’s entirely possible that the very wildlife population organizations like the Humane Society are trying to protect will suffer.

Most existing evidence is incomplete or contradictory. Organizations opposed to traditional ammunition cite studies like those from the Peregrine Fund that indicate lead poisoning in California condors to support their position. Yet at the population level, raptor species like the California condor continue to thrive.

On the flip side, after testing blood lead levels of residents for over 15 years, the Iowa Department of Public Health has not found elevated lead levels resulting from ingestion of hunted venison. Much of the contradiction seems to arise from the difficulty of linking lead related issues directly to ammunition without regard for other potential sources like landfills.

Many challenge studies supporting lead ammunition bans because they believe there is not adequate evidence to assign cause to lead ammunition. Pro-hunting groups point to U.S. Geological Survey data that shows only 5 percent of domestic lead production supports manufacture of ammunition, so who’s to say that the other 95 percent of lead used in products like paint, gutters and industrial projects aren’t to blame for game poisoning?

While the Humane Society cites large numbers of lead-induced mortality among birds, other data contradicts this position. According to data published by the U.S. Fish and Wildlife Service, lead ingestion is among the lowest contributors to bird mortality. Estimated at 0.7 percent, lead falls well below other factors, including loss of habitat (33 percent), collisions with structures (32 percent), domestic and feral cats (17 percent) and licensed hunting (1 percent).

Moreover, different types of ammunition use lead in different ways — potentially with radically different impacts on the environment. For example, shotgun shells disperse pellets, some of which remain in the animal while others fall to ground or water. Rifles and pistols generally use jacketed projectiles that tend to remain in the animal. Do these have similar, if any, impact on wildlife populations?

Regardless of the disagreement in the scientific community, the march towards ban of traditional ammunition use is proceeding. On the heels of the California lead ammunition ban being signed into law, it appears that Oregon is the next target.

This month, the Oregon Department of Fish and Wildlife and Oregon State University will launch a random survey to 4,200 hunters across the state inquiring about use of lead ammunition and knowledge of alternatives. While no proposals are in place, many are suspicious that the project will lead to traditional ammunition ban proposals.

In light of the controversy, the Arizona Game and Fish Department may have the best solution of all. Not supportive of mandatory bans, the department has demonstrated great success with education supporting voluntary lead reduction programs in the California condor’s core range.

Prior to the education programs, less than 4 percent of ammunition used was lead free. For the past two years, 88 percent of hunters have taken advantage of lead reduction programs says Arizona Assistant Director of Wildlife Management Jim deVos.