BRENTWOOD -- A man participating in a fishing competition died Saturday after the boat he was riding in struck a rail crossing support in the Delta.

The boater was only identified as a 40-year-old man from Mountain Home, according to Contra Costa County Sheriff's Office spokesman Jimmy Lee.

Two men were aboard the boat when it struck a rail crossing support in Old River. east of the Cruiser Haven Marina, 7000 Orwood Road, Lee said.

The incident occurred shortly before 11:30 a.m., and both men were thrown into the water. The pilot suffered minor injuries and was treated at the scene, while the search continued for the passenger. Both men were wearing life jackets, a Sheriff's Office official said.

Alcohol is not considered a factor in the accident, and it is not known whether the boat was speeding.

The railroad bridge is owned by BNSF Railway and is used for both freight and passenger trains on Amtrak's San Joaquin line. Rail traffic was halted while searchers worked in the area but resumed by mid-afternoon. A Coast Guard helicopter assisted with the search.

The site of Saturday's fatality, known as Orwood, is less than two miles from Indian Slough and the entrance to Discovery Bay. The area has long been popular with recreational boaters, but its hazards have been well documented over the years.

Sheriff's Marine Patrol officials say that part of the river is dangerous because it is a popular watercraft-launching area that leads to narrow, congested waterways around Indian Slough. There were at least two fatal boating accidents in the area in 2009, and other incidents resulting in injuries have occurred more recently.

Staff writer Eve Mitchell contributed to this story. Follow Katie Nelson at Twitter.com/katienelson210. Follow Karina Ioffee at Twitter.com/kioffee