HOUSTON, Dec. 15, 2004 - Environmental Remediation Holding Corporation ("ERHC") (OTCBB:ERHC) announced today that it has signed an additional participation agreement with Pioneer Natural Resources Company (NYSE:PXD) whereby the companies will jointly evaluate and negotiate participation in Block 3 of the Nigeria/Democratic Republic of Sao Tome and Principe Joint Development Zone ("JDZ") in the Gulf of Guinea, offshore West Africa.

"This makes the second agreement with Pioneer in the JDZ. I believe it demonstrates Pioneer's commitment to the region," commented Mr. Ali Memon, president and CEO of ERHC.

ERHC is an oil and gas company focused on exploration in the Gulf of Guinea offshore West Africa. ERHC's headquarters are in Houston. For more information, visit ERHC's Web site at www.erhc.com.

Pioneer Natural Resources is a large independent oil and gas exploration and production company with operations in the United States, including the Deepwater Gulf of Mexico, Argentina, Canada, Equatorial Guinea, Gabon, South Africa and Tunisia. Pioneer's headquarters are in Dallas. For more information, visit Pioneer's Web site at www.pioneernrc.com.

The statements in this document are forward-looking statements made pursuant to the Safe Harbor Provisions of the Private Securities Litigation Reform Act of 1995. These statements and the business prospects of ERHC are subject to a number of risks and uncertainties that may cause actual results in future periods to differ materially from the forward-looking statements. These risks and uncertainties are described on Forms 10-Q and 10-K filed with the Securities and Exchange Commission.