Investigators from the federal Occupational Safety and Health Administration were working to determine the cause of the collapse of a 6-foot-by-9-foot portion of the roof.
"He went up there to show his three employees what he wanted done," Hofman said. "But he was the only one who wasn't harnessed in."
Emergency crews spent more than an hour digging out the second man. Police have not released his name, and information on his condition was not immediately available Monday evening. Hofman said the man's injuries did not appear to be life-threatening. The two other workers were unharmed.
Most students remained unaware of the accident, school spokeswoman Cathy L. Skitko said. The building, which houses heating facilities, is on the campus' northwest corner and "quite removed" from any classroom structures, she said. Classes continued throughout the day and were expected to be held Tuesday as scheduled.
Sensenig, 47, had worked at his family's roofing and industrial metals business for more than 30 years, according to the company website. He and his brothers first began using their summer breaks and holidays to pitch in at the office his father opened in 1958.
The brothers all held executive positions in the family business. On Monday evening, a woman who answered at one of the brothers' homes and declined to give her name said Sensenig's death had left the family and the business in a "tough place."
Hill had contracted with R.L. Sensenig several times in the past and had no reason to question the company's work-site safety record, Skitko said.
"We're very sad about this," she said. "And, again, we express our sympathies."
Contact staff writer Jeremy Roebuck at 610-313-8212 or jroebuck@phillynews.com.
