HOUSTON—A collision between an oil tanker bound for Exxon Mobil Corp.'s Beaumont refinery and an outbound vessel towing barges resulted in a major crude-oil spill in the port of Port Arthur, Texas on Saturday.

The U.S. Coast Guard says about 450,000 gallons of crude oil has spilled into the Port of Port Arthur area in southeast Texas after two vessels collided. Video courtesy of Fox News.

The...