 In 1988, Star Enterprises, a company started when Saudi Aramco bought half interest, took over the refinery until 1998, when Motiva Enterprises, a joint venture between Star (Saudi Aramco) and Shell, operated it.Motiva's operation was the most controversial, with many lawsuits resulting from an explosion and many federal emission regulations violations.Premcor Refining Group bought the refinery from Motiva in 2004, but Valero acquired Premcor a year later.