BOISE, Idaho – The meat in your freezer from the deer you shot last fall may be contaminated with tiny fragments of lead from the bullets that killed it.

A study released Tuesday by the Peregrine Fund and Washington State University shows that people who consume venison from game animals killed with lead bullets risk ingestion of the poisonous metal.

Tiny amounts of lead can cause brain development problems in children.

Even amounts previously considered safe in adults are now known to increase rates of death from heart attack and stroke.

“X-rays revealed that processed ground venison from 80 percent of the deer sampled in the research contained metal fragments,” said Rick Watson, vice president of Boise-based group, The Peregrine Fund, a raptor conservation organization.

The concern was high enough in North Dakota that health officials there pulled hunter-donated venison from food pantries in March after lead was found in 60 percent of meat tested.

“This isn’t a food pantry problem, this is a nation-wide problem,” said William Cornatzer, who pushed for the North Dakota ban told The Associated Press.

But Cornatzer’s sampling was not done randomly and raises questions about its validity, said Taylor Gross, a spokesman for the Safari Club International a hunters conservation group.

“If we’re going to start taking away venison and other game meat from food banks and homeless shelters it had better be because of sound science and thoughtful academic research with no agenda,” Gross said.

He had not seen the new study released Tuesday, but Gross said he was watching the research on the issue.

“If true sound science indicates adjustments need to be made then the Safari Club will support those adjustments.”

The study was released at a conference of scientists, biologists and health experts at Boise State University on the effects of lead bullets on humans and wildlife. Previous studies have found lead residues in birds of prey and scavengers including California Condors the Peregrine Fund has reintroduced into Arizona.

Researchers sampled 30 white-tailed deer killed under normal hunting conditions in northern Wyoming with standard lead-core, copper-jacketed bullets fired from a high-powered rifle. X-rays of all 30 deer show widespread dispersal of lead fragments in the carcasses consistent with previous research, said Watson. The fragments ranged in size from smaller than a grain of table salt to as large as a sesame seed.

“Some of it was closer to dust than a measurable fragment,” Watson said. “Without an X-ray, you would never know it was there.”

For the study, each of the 30 carcasses was taken to a different commercial meat processor for standard preparation of ground meat and boneless steaks in 2-pound packages. Even though processors routinely cut out and discard meat around the wound and along the bullets path inside the animal, fragments still ended up in packaged meat.

In addition to the ground meat packages, metal fragments also were found in packages of steaks. Of 16 deer carcasses with metal fragments near the spine, four showed fragments in the loin steaks. Some individual packages of both ground meat and steaks showed up to nine lead fragments, while others showed few or none, making it difficult for consumers to predict which packages might contain lead.

“Our results suggest that people may frequently ingest metallic lead when they consume deer killed with lead-based bullets and processed by normal procedures,” Watson said. “Fortunately, using copper bullets is a viable option to avoid the risk of lead exposure.” Previous Peregrine Fund research showed that the large scavengers were poisoned after feeding on carcasses and gut piles from hunter-killed game. In 2007, 80 percent of Arizona hunters voluntarily used non-lead ammunition in condor country or removed deer gut piles after learning about the effects of lead on condors. Condor deaths dropped from four in 2006 to none in 2007.