KANSAS CITY, Mo. -- A federal agency is investigating after firefighters had to rescue a man trapped in a mud trench at a Kansas City work site.

The U.S. Department of Labor's Occupational Safety and Health Administration said in a news release it's investigating the collapse that occurred Wednesday at an apartment complex.

OSHA said an employee of Hydro Tech Plumbing was injured after the trench he was working in collapsed. The worker was repairing underground sewer lines in a trench more than 10 feet deep. OSHA said it's investigated collapses in which 23 workers have died since January.