Amerada Hess Corporation
Mobil Corporation
Amoco Corporation
Motiva Enterprises, L.L.C.*
Anadarko Petroleum, Inc.
Occidental Petroleum Corporation
Atlantic Richfield Co. (ARCO)
Phillips Petroleum Company
BP America, Inc.
Shell Oil Company
Burlington Resources Inc.
Sonat Inc (acquired by El Paso Energy)
Chevron Corporation
Sunoco, Inc.*
CITGO Petroleum Corporation*
Tesoro Petroleum Corporation*
Clark Refining and Marketing, Inc.*
Texaco
Coastal Corporation
Tosco Corporation*
Conoco, Inc. (Conoco)
Ultramar Diamond Shamrock Corporation*
Enron Corporation
Union Pacific Resources
Equilon Enterprises, L.L.C.*
Unocal Corporation
Exxon Corporation
USX Corporation
Fina, Inc.
Valero Energy Corporation*
Kerr-McGee Corporation
Williams Companies, Inc.*
Lyondell-CITGO Refining, L.P.*
* Denotes new survey entrant in 1998.