SoCal Gas Company
American Hunter Exploration, Ltd.
Premier Consolidated Oil Field (U.K.)
Meridian Oil, Inc.
El Paso Natural Gas Company
TRANSCO Pipeline
Merrion Oil and Gas Company
Robert L. Bayless Production
EG&G Corp.
Tetra Tech Corp.
Dames & Moore, Inc.
SAIC Inc.
PRC Environmental Management
Southwest Public Service Sunshine Drilling and Exploration
Richmond Petroleum, Inc.
Northwest Pipeline Corporation
Stephens, Inc.
Coastal Oil and Gas Corporation
BHP Petroleum (Americas) Inc.
Allsup
Vulcan Materials Company