DURHAM (WTVD) -- A construction worker is in critical condition after he was injured Wednesday while using a portable toilet at work.Durham Police identified him Thursday as 38-year-old Jesse Zimmer.Police said the incident happened around 3:30 Wednesday afternoon at a construction site in the 400 block of Morris Street.Officers said Zimmer was inside of the portable toilet when a large metal beam fell off of a building from five stories up and hit the portable bathroom, crushing it."We called 911 with some other guys. We tried to figure out what was going on," said Luis Carmona, who was arriving to pour concrete at a nearby construction site when the incident happened.Zimmer was taken to the hospital.Carmona said he has seen accidents before but this one left him "shocked."The 15-acre construction site covers the entire 400 block of Morris Street at Hunt Street.It's the first phase of the $100 million Durham Innovation District - two seven-story buildings of research labs, retail, and restaurants.Raleigh-based Barnhill Contracting is in charge of the project.Department of Labor records show two serious accidents on Barnhill sites since 2008.ABC11 reached out to Barnhill but did not hear back Wednesday.As of late Wednesday evening, the injured worker remained in critical condition. He remained hospitalized Thursday, police said."It could've happened to anybody," Carmona said. "It could've been me, or anybody else."