Mr. Hartwig said that 30 percent of returning troops exhibit mental problems and 4.2 percent of those coming back from Iraq are physically injured.

"Can you provide accommodation for the possibility of reinjury and lack of mental treatment?" he asked his audience.

Mr. Hartwig said businesses should be aware of mental health issues, noting that the Veterans Health Administration spent $4.3 billion last year to treat veterans for post traumatic stress disorder.

Another emerging issue, he highlighted, is the impact of obesity-related claims, which he calculated account for 4 percent of workers' comp expenditures.

According to his figures, 31 percent of the U.S. population is obese and 30 percent is overweight. "Workers of the future will be obese in record proportions."

Mr. Hartwig estimated the impact of obese workers on the workers' comp system will be $1.1 billion this year alone. That figure, he said, does not include claims related to workers who are overweight but not enough for the obese category.

The problem of obese workers, Mr. Hartwig said, is most acute in the Southern and Midwestern regions of the country.

Jennifer Tomilin, senior vice president, Zurich North America, warned of the possible impact of manganese exposure on employees doing welding work. She said although there is currently no conclusive link, some studies have shown a connection to Parkinson's disease.

Noting the vast number of welders in the work force over the years, Ms. Tomilin cautioned, "Think how many old claims could come through the door if a [Parkinson's] link is proven."

She warned of potential claims from silica dust, noting that 51 types of businesses have such exposure. Another exposure is beryllium, used in dental laboratories.

Mr. Hartwig also sounded an alarm about degenerative neurological disease, which appears to be concentrated in a variety of occupations. Trial lawyers, he said, are preparing to seize on such cases as a new frontier on which to bring comp claims.