AALADIN SOUTHWEST

ANADARKO

AKA ENERGY

ANR PIPELINE

ALON USA, LP

APOLLO RESOURCES INTERNATIONAL

ALTURA ENERGY LTD

ATALAS PIPELINE CO

AMOCO PRODUCTION CO

BEAR PAW

BITTER CREEK PIPELINES, LLC

BEELINE GAS SYSTEMS

BLACKHILLS GAS RESOURCES

BENSON-MONTIN-GREER

BOBBY HIGGINS WELL SERVICE

BIG HORN GAS GATHERING

BP

BINGER OPERATIONS

BURLINGTON RESOURCES

CALPINE NATURAL GAS

CHEVRON TEXACO

CANTERA GAS CO

CITGO

CANYON GAS RESOURCES

CMS PANHANDLE EASTERN PIPELINE CO

CAULKINS OIL CO

COFFEYVILLE REFINING & RESOURCES

CDX GAS, LLC

COLORADO INTERSTATE GAS

CELANESE

COMPRESSOR SYSTEMS, INC

CELERO

CONOCO PHILLIPS

CENTER POINT ENERGY

CONTINENTAL GAS, INC

CENTRAL RESOURCES

COOPER ENERGY

CHESAPEAKE ENERGY

CROSS TIMBERS OPERATIONS CO

CHEVRON

CROSSTEX ENERGY SERVICES

DCP MIDSTREAM

DOMINION EXPLORATION (NOW CALLED HIGHMOUNT)

DEVON

DORCHESTER MINERALS OPERATING, LP

DIAMOND SHAMROCK REFINING CO, LP

DUGAN PRODUCTION

DIAMOND - KOCH

DUKE ENERGY

EAGLE ROCK ENERGY

ENERGEN RESOURCES

EL PASO CORP

ENERGY TRANSFER CO

ELKHORN

ENERVEST OPERATING

ELM RIDGE

ENERVEST OPERATING

ENBRIDGE

EQUISTAR CHEMICALS

ENCANA

EXXON MOBIL

ENCORE

FINA

FRONTIER FIELD SERVICES

FIRST ENERGY SERVICES CO

GIANT REFINING

GULF SOUTH PIPELINE CO, LP

GPM GAS CORP

HALLWOOD ENERGY CO

HILAND PARTNERS, LP

HANOVER CO

HOUSTON PIPELINE

HESS CORP

J. CLEO THOMPSON

JUNIPER DEVELOPMENT

JM HUBER CORP

JW POWER COMPANY

JACK SIMMS INDUSTRIAL

KERR-MCGEE

KOCH EXPLORATION

KINDER MORGAN

LANCE OIL & GAS

LYONDELL - CITGO

LIVELY EXPLORATION

MALLON OIL CO

MERIT ENERGY CO

MARATHON OIL CO

MOUNTAIN GAS RESOURCES

MARK WEST RESOURCES, INC

NAVAJO REFINING CO

NORTHWEST PIPELINES

NIKA ENERGY

NORTHWINDS OF WYOMING

NORTHERN NATURAL GAS

ONCOR

OXY

ONEOK

PANHANDLE EASTERN PIPELINE

PLAINS EXPLORATION

PHELPS DODGE MIAMIM INC

PRODUCION OPERATORS

PHOENIX HYDROCARBONS

PURE RESOURCES

POINEER NATURAL RESOURCES

PVR MIDSTREAM

QUESTAR GAS MANAGEMENT CO

QUIXX POWER SERVICES

RED CEDAR GATHERING

RIM SOUTHWEST

RED WILLOW PRODUCTION

RIO CHAMA PETROLEUM

REGENCY GAS SERVICES

RIVER GAS

RICHARDSON OPERATING CO

ROWDY PIPELINE

SAGLE & SCHWAB ENERGY RESOURCES

SINCLAIR WYOMING REFINING

SAMSON

SOUTH TEXAS TREATERS

SCHLUMBERGER

SOUTHERN STAR CENTRAL

SEMPRA

SOUTHERN STAR CENTRAL

SG INTERESTS

SUNCOR ENERGY

SID RICHARSON ENERGY SERVICES

SUPERIOR PIPELINE CO

TARGA RESOURCES

THOMPSON ENGINEERING AND PROD

TENNESSEE GAS PIPELINE

TICONA POLYMERS, INC

TEPPCO NATURAL GAS

TIMBERLAND GATHERING

TERRA INDUSTRIES

TIMBERLAND GATHERING

TEXACO EXPLORATION & PRODUCTION

TRANSWESTERN PIPELINE CO

TEXAS TREATERS

TREND GATHERING & TREATING

THE RIM COMPANIES

ULTRAMAR DIAMOND SHAMROCK

UNIVESAL COMPRESSION

VALERO

WALSH ENGINEERING & PROD

WILLIAMS

WESTERN GAS RESOURCES

WILLISTON BASIN

WHITING OIL & GAS

WYNNEWOOD REFINING

XTO ENERGY