CAMERON, Mo. -- Officials said soil samples taken from around an old insulation fiber plant in northwest Missouri revealed elevated amounts of arsenic and lead, but not at hazardous levels.

About 250 people heard state and federal officials discuss the findings at a public meeting in Cameron Thursday night. Soil samples around to the former Rockwool Industries plant were tested as part of an investigation into the numbers of brain tumors in Cameron.

Officials said that through mid-August, 68 people had returned survey forms reporting an instance of tumors in the brain or central nervous system.

If verified cases make up a so-called "cancer cluster," further investigation will be conducted.

Some of the residents at the meeting expressed frustration that officials didn't have more answers.

"We don't want to yell, 'Fire!' if we don't know where the fuel's at or if there is any fuel," one city official told the Cameron residents gathered.

"I heard no answers. I heard absolutely no answers," said one frustrated resident after the meeting. "And the information they were throwing out was relevant to what?"

Another meeting is planned for September, although no date has been set.