By Natasha Brown

PHILADELPHIA (CBS) — Authorities in Philadelphia are investigating a deadly construction accident in University City. One worker was killed and another was injured when a large drilling rig toppled over Tuesday night.

The investigation into the deadly construction site accident is continuing at this hour as officials try to figure out what lead to the death of a construction worker Tuesday night.

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After several hours and an ongoing investigation, the drill rig involved in a deadly accident in University City was removed from the scene.

The tragic incident happened around 8:30 p.m. Tuesday near the University City/Penn Medicine SEPTA station stop on Convention Avenue.

Officials say heavy equipment was being moved off a tractor-trailer to the worksite when a drilling rig being used to lift equipment toppled under the upper mast.

A 55-year-old worker became trapped underneath.

It took about 15 minutes to extricate the worker. He was pronounced dead at the hospital. Another worker was also injured.

CBS3 spoke with the operations coordinator at Cook Drilling in Bucks County. They said it was one of their employees who was operating the drill rig at the time.

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He suffered minor injuries and was treated and released from the hospital. The man who was killed is believed to have been an inspector who did not work for their company.

Meanwhile, Cook Drilling said they’ve been working on this site since about June 23 and that their employee is an experienced equipment operator.

Philadelphia’s Licenses and Inspections is investigating and so is Occupational Safety and Health Administration. OSHA released the following statement on Wednesday:

“The Occupational Safety and Health Administration’s Philadelphia Area Office is investigating yesterday’s fatal incident in University City. A piece of construction equipment tipped over, fatally striking one employee and injuring the equipment operator. OSHA will conduct a thorough investigation of the incident and any related hazards to employees at the worksite. By law, OSHA has up to six months to complete the investigation.”

Attorneys who handle cases like this say there could be civil and criminal actions if that’s deemed necessary. Meantime, they say they are involved oftentimes just to prevent things like this from happening again.

“We’re always looking, No. 1, to make sure that civil justice is done for a family that suffers a loss of this type, but we’re looking for other similar accidents,” attorney David Kwass said.

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Cook Drilling has been in business since 1955. The company said this is the first fatal accident in its history.