Crum, 39, was operating a boom lift and unloading equipment from a trailer when the lift struck overhead power lines, the Liberty County Sheriff's Office said Monday.
Let our news meet your inbox. The news and stories that matters, delivered weekday mornings.
"This electrified the boom lift electrocuting Coach Crum," the department said.
Crum's wife, Shana, 41, was electrocuted trying to help her husband, and their 14-year-old son, Chase, was shocked trying to help his parents, authorities said.
The couple died at the scene, authorities said. Chase was taken to the hospital and is expected to recover.
Shana Crum was a health aide in the Liberty County School District, said David Summers, the Liberty County School District's superintendent. Her husband was the head baseball coach.
More than 20 people, including players from the baseball team and parents, were present when the accident happened. The students were bused to the high school's gym where grief counselors were made available.
"The district is assigning additional School Resource Deputies to support students, parents and staff," Summers said. "Our thoughts and prayers go out to those impacted by this tragedy."
Officials called the deaths a "tragic event which has rocked our community to its core."
Minyvonne Burke is a breaking news reporter for NBC News.