Ten to 15 percent of the nation's construction workers have a substance abuse problem, costing the U.S. economy more than $10 billion annually, according to a University of Michigan survey.

William F. Maloney, U-M associate professor of civil engineering and a former construction engineer who headed the recent national survey, said at least 600,000 of the nation's 6 million construction industry employees have a substance abuse problem.The findings of the survey, the first of its kind to concentrate solely on the construction industry, already have prompted action.

"More than 100 contractors and architectural firms are taking the report, examining the findings, and developing programs and workshops to combat the problem," Maloney said.

For the study more than 300 contractors and designers were asked to assess the extent of substance abuse throughout the industry and among their rank and file.

"Abuse was defined as use of any illegal substances, including marijuana, cocaine, barbiturates, amphetamines, heroin and hallucinogens," Maloney said, "or the misuse of legal drugs such as alcohol or Valium to the degree that it impairs a worker's ability to perform at levels consistent with industry standards."

Maloney said it was no surprise which of the substances was seen as the most abused. "Although many people do not consider it a drug, alcohol is the most abused drug by a significant margin," Maloney said.

Of the 250 contractors who responded, 136 said they perceived a serious drug problem throughout the industry, while only six reported no problem at all. Fifty-one said the problem among their own employees was serious, compared with 138 who said substance abuse "in-house" was not serious. On the average, contractors estimated that 9.7 percent of their employees were substance abusers.

Contractors, whose ranks include on-site laborers and supervisors, said substance abuse is responsible for 18.8 percent of all cases of absenteeism and 14.9 percent of work-related injuries.