Westfield Montgomery Mall construction accident due to malfunctioning jack

The enormous concrete slab slipped during the accident, crushing two workers. Photo: ABC7

(WJLA) - The failure of a jack assembly led to the collapse of a portion of a Montgomery County mall parking garage that killed one worker and seriously injured another, a report on the incident concludes.

In an executive summary on the May 23 incident at the Westfield Montgomery Mall in Bethesda, investigators say that that the scaffold legs of a jacking tower at the construction site where the accident happened were not being used properly, causing it and a portion of the garage to come down.

Carroll Dexter Wills, 57, was killed in the accident. Another worker suffered serious injuries.

Montgomery County Fire officials say that a large concrete slab of the garage, which was under construction at the time, fell during the accident, crushing the workers. The garage, which is attached to the mall's food court, was expected to reopen this autumn.

According to the investigation, which calls the incident a "tragic construction incident," a safety tower at the garage began to twist and fail. At that point, workers jacked up a tee in an effort to remove the beam.

At that point, though, investigators say that the scaffold legs of the jacking tower were extended beyond manufacturers recommendations; at the same time, its extension sections were not braced properly. Those two missteps reduced the load capacity of the jack, causing it to fail.

ABC7's Brianne Carter contributed to this report