Minnesota officials have tested 1,239 samples of venison donated to food shelves last fall and found that 273, or 22 percent, had evidence of lead bullet fragments.
That percentage is similar what was announced in April after about 300 samples had been examined with X-ray equipment.
But the extent of the issue continues to surprise and perplex officials.
Because all of the donated venison was processed commercially, some have suggested that careless processors might be at least partially to blame.
But the Minnesota Department of Natural Resources collected and tested 123 samples from DNR employees who processed their own deer themselves. They found about 18 percent had some lead contamination.
"I was shocked," said Lou Cornicelli, DNR big-game program manager and a deer hunter whose own venison had some lead contamination. "I'm pretty careful how I trim around wound channels."
The latest information came as 40 wildlife, health and agriculture officials from seven Midwest states gathered Wednesday in Bloomington to discuss how to respond to what has become a major wildlife and health issue.
"This isn't a state issue, it's a national issue," DNR Commissioner Mark Holsten said. "It's not going away."