The injured crew member was taken to Christus Spohn Hospital Corpus Christi-Memorial, where he was listed in critical condition, said Ed Mickley, public affairs spokesman for the Naval Mine and Anti-Submarine Warfare Command.
The Navy MH-53 Sea Dragon helicopter was part of Helicopter Mine Countermeasures Squadron 15 out of Naval Air Station Corpus Christi, Mickley said.
It was on a routine training mission when it went down about 8:15 p.m. Wednesday in a farmer's field south of the intersection of Farm Roads 2444 and 665, about 4 miles south of Corpus Christi, he said.
Lt. Sean Robertson, a spokesman for NAS Corpus Christi, told the Corpus Christi Caller-Times the crash happened during heavy fog. The newspaper said downed power lines hindered the efforts of the first rescuers.
The crash caused a fire, but Corpus Christi firefighters as well as volunteer firefighters from a number of communities helped put out the flames.
J.D. Batten, who lives about two miles from the crash site, told the Corpus Christi Caller-Times that he was walking near his property's front gate when he heard a helicopter overhead.
"Suddenly I saw a red-glowing fireball shoot hundreds of feet up into the air," he said. "I heard a giant boom a second later. It was then dead silent and I couldn't hear the helicopter anymore."
Searchers initially set up a perimeter of about 200 yards around the crash site, but the restricted zone was expanded as the search continued for the missing crew members, Mickley said. It was unclear what the weather was like at the time of the crash, he said.