Washington ? Workplace suicides surged 28 percent last year, the Labor Department said Thursday, as anxious workers dealt with a struggling economy and watched colleagues depart in a rash of layoffs.

At the same time, the agency’s Bureau of Labor Statistics said the total number of workers who died on the job from any cause fell by 10 percent.

The 5,071 workplace fatalities recorded in 2008 was the lowest number since the agency began tracking the data in 1992. That number includes 251 suicides, the highest number since official reporting began.

Labor officials did not seek to explain the sudden rise in workplace suicides. A BLS spokesman said the agency plans to research it more extensively.

The agency says economic factors could be responsible for the overall decline in fatalities.

Workers on average worked 1 percent fewer hours last year and the construction industry — which usually accounts for a major share of accidental workplace deaths — posted even larger declines in employment or hours worked.

Gary Chaison, a professor of industrial relations at Clark University in Worcester, Mass., said the numbers suggest the struggling economy taking a toll on worker morale.

“Those who are at places where there have been substantial layoffs are trying to cope with survivor’s guilt,” Chaison said. “I also think there’s tremendous anxiety in the American workplace. It’s not just being anxious, it’s being depressed.”

But Chaison cautioned both numbers may be at temporary extremes that will drift toward historic levels once employment rises and economic conditions improve.

Labor Secretary Hilda Solis called the decline in workplace fatalities a “change in the right direction,” but said it does not lessen the need for stronger safety enforcement to prevent accidental injuries.

The report is based on preliminary numbers that could change once the final report is released next year.