Air Pollution Control Equipment Services, Coal

Arch Coal to invest $1.3 million in ADA-ES

LITTLETON, Colo., July 17, 2003 — ADA-ES, Inc., a subsidiary of Earth Sciences, Inc., announced that it has signed a $1.3 million Securities Subscription and Investment Agreement with Arch Coal Inc., subject to completion of the spin-off of ADA-ES as a separate public company and certain other conditions.

The second largest coal producer in the U.S., Arch Coal is a joint venture partner of ADA-ES and has provided financial support on several mercury control programs.

Pursuant to the investment agreement, Arch is expected to purchase, shortly after the spin-off, (1) a $300,000 convertible debenture from the Company (the “Debenture”), (2) $1.0 million of common stock, and (3) options to purchase 50,000 additional shares of common stock. $300,000 of the proceeds from the Arch investment will be used to reduce indebtedness of Earth Sciences to be assumed by ADA-ES upon completion of the spin-off.

The price per share for the $1.0 million of ADA-ES common stock would be the lesser of ten times 200% of the 20-day average price of the Earth Sciences common stock before completion of the spin-off or $10 per share. Following completion of the spin-off and the Arch investment, there are expected to be approximately 3.6 million shares of ADA-ES outstanding.

As part of the terms of the transaction, Arch will appoint a member to ADA-ES’ Board of Directors.

In January 2002, ADA-ES and Arch entered into a joint venture to market ADA-ES’ product, ADA-249, to cyclone-fired power plants. ADA-249 enables these plants to burn less expensive coal (Powder River Basin “PRB” coal), enhance operational flexibility and improve the marketability of combustion by-products, all without increasing emissions. The JV provides Arch’s customers with a long-term package of PRB coal, the ADA-249 chemical and, if needed, the required injection equipment.

Dr. Michael Durham, President of ADA-ES, stated, “We are pleased to further strengthen our relationship with Arch as we pursue mutual interests. ADA-ES has a reputation for developing cost-effective and innovative technology to reduce mercury emissions from coal-fired boilers. We look forward to consummating the investment after the spin-off, which we expect to complete in the next 60 days.”

“The use of coal creates tremendous advantages for the U.S. economy in the form of lower energy costs, greater energy independence, and increased competitiveness in the global arena,” said John W. Eaves, Arch Coal’s Executive Vice President and Chief Operating Officer. “At the same time, new technologies have made coal an increasingly clean fuel source for electricity generation. We are enthusiastic about the work that ADA-ES is doing in an effort to achieve even greater advances in emissions control technology.”

Coal is the source of approximately 50% of the electricity that Americans use each day.

Additional information on Arch’s investment, including pro forma financial information, is available in ADA-ES’ Form 10-SB, as amended, filed with the Securities and Exchange Commission on March 24, 2003.

About Arch Coal

Arch Coal is the nation’s second largest coal producer with subsidiary operations in West Virginia, Kentucky, Virginia, Wyoming, Colorado and Utah. Through these operations, Arch Coal provides the fuel for approximately 6 percent of the electricity generated in the United States.

About ADA-ES

Headquartered in Littleton, Colorado, ADA-ES, Inc., a subsidiary of Earth Sciences, develops and implements proprietary environmental technology and specialty chemicals that mitigate the environmental impact from electric power and industrial companies while reducing operating costs.