A construction crane several stories tall toppled onto a pump station just north of the Trinity River in Dallas this morning.

Two City of Dallas employees were injured, but no fatalities were reported.

The incident occurred about 10 a.m. at the City of Dallas' Old Hampton pump station near the intersection of Conveyor Lane and Inwood Road and south of Interstate 35E.

Dallas Fire-Rescue Sherrie Lopez said workers were installing a piece of a pump when the crane tipped over and fell onto the building, trapping a 56-year-old worker on the roof and crushing his legs. The crane also fell on two vehicles parked nearby, injuring another man on the head.

Ms. Lopez said it was fortunate no more injuries were reported. At the time of the accident, three workers were on the ground, three people were in the station and one person was on the roof.

The injured employees were transported to Parkland Memorial Hospital. Their conditions were not immediately known.

It was unclear at this point exactly why the crane tipped over, but weight may have been a factor, Ms. Lopez said. The crane was installing a piece of pump that housed the pipe and weighed about 1,800 pounds.

"We're trying to put together the pieces of what happened," Ms. Lopez said.

Workers had removed the pump about a month ago for maintenance, said Kelly High, interim street services manager for the City of Dallas. This type of service is done 18 or 19 times a year, and Mr. High said it was the first time workers had encounted an incident such as this.

The crane belonged to the Louisiana Crane Company, Ms. Lopez said. Two cranes will be brought in to remove the fallen crane from the scene.