Also known as:
1943 - As Clark, acquired Blue Island, Illinois refinery
1965 - Shuts down Marrero, Lousiana refinery
1968 - Acquired Hartford (Wood River), Illinois refinery from Sinclair
1981 - Company acquired by APEX (but remains Clark)
1987 - Files for bankruptcy
1992 - Acquired by Horsham (but remains Clark)
1995 - Acquires Port Arthur refinery from Chevron
1998 - Acquires Lima refinery from BP
1999 - Company acquired by Blackstone and Occidental (but remains Clark)
2000 - Name changed to Premcor
2001 - Shuts down Blue Island, Illinois refinery
2003 - Sells Hartford (Wood River) refinery to ConocoPhillips
2003 - Acquires Memphis refinery from Williams
2004 - Acquires Delaware City refinery from Motiva
2005 - Company acquired by Valero