The tugboat Wally Blessey was pushing a barge loaded with lube oil when a fire broke out in the engine room just before it passed under the Queen Isabella Causeway late Sunday night.
The tug's captain notified the Coast Guard at South Padre Island and two 27-foot rescue boats safely pulled the crew from the burning vessel within 12 minutes. The barge was disconnected and towed away by another tugboat.
The Intracoastal Waterway was closed to traffic until about 3:45 a.m. Monday, the Coast guard said.
The Coast Guard Marine Safety Satellite Office at Brownsville is investigating the incident.