The company that reportedly was involved in the May 19 oil spill off the Gaviota coast is a large Houston-based master limited partnership that operates nearly 18,000 miles of pipeline in the U.S.

The company, Plains All American Pipeline, also operates a number of processing facilities and is organized as a so-called master limited partnership that passes most of its income along to investors.

Shares closed at $49.59 on the New York Stock Exchange on May 19. The company has not commented on the spill but Coast Guard officials identified one of its on-shore facilities as the source of the leak, which by late afternoon had created a four-mile-long slick near Refugio Beach.

Santa Barbara was the site of a disastrous 1969 offshore oil spill that helped spark the beginning of the nation’s environmental movement.