Three Maryland construction workers drowned in a flash flood last week while repairing a culvert running beneath an interstate highway, according to an article in theBaltimore Sun.

Their employer had a history of workplace safety violations, most recently for trenching violations, according to state and federal records cited in the article.

A crane operator for Concrete General, Inc. was killed on the job in 1988. Another employee's arms had to be amputated after he was shocked by a power line in 1982, and a Concrete General worker was rescued after a trench collapsed in 1995, according to the article.

Workers had begun the $250,000 highway project last week and were cleaning the culvert's seals to prepare it for welding, said a spokeswoman for the State Highway Administration.

A key issue in the investigation is whether Concrete General supervisors or employees informed the workers that a flash flood watch was in effect in most Maryland counties on the day of the incident, Keith Goddard, commissioner of the Division of Labor and Industry, told the newspaper.

Baltimore County officials believe that ten men were working near the culvert when the drownings occurred.

Many workers are not aware of the dangers of flash flooding, said Andy Miller, an associate professor at the University of Maryland, Baltimore County, in the article. The combination of impervious surfaces – parking lots, sidewalks, roofs – and a very efficient storm-drain network concentrates large flows of rainwater into places like the culvert, he said.