The Environmental Protection Agency has taken its first step toward regulating the commercial release of genetically altered organisms into the environment by announcing requirements governing such releases.

Genetically altered organisms used as pesticides cannot be released into the environment without notifying EPA, the agency said in a letter sent Thursday to Jeremy Rifkin, president of the Foundation on Economic Trends.

Rifkin had sued successfully to block the release of a genetically altered microbe in a university experiment, but that court decision did not prohibit a private company from conducting the identical experiment.

Rifkin petitioned the EPA in June to require experimental-use permits for all genetically altered pesticides released into the environment, including those released by private companies.

EPA answered the petition by saying that it will require notification of a proposed release and will determine if an experimental-use permit is required. To obtain a permit, a company or scientist would have to submit detailed information that would help the agency assess potential environmental risks and, perhaps, impose safeguards.

The agency said it is in the process of "developing procedures and data requirements to address specific issues of health or environmental concern for genetically manipulated microbial pesticides," and would require notification as "an interim procedure."

The National Institutes of Health must approve the release of genetically engineered organisms in experiments conducted by universities receiving federal funds, but private companies need not obtain NIH permission.

In May, U.S. District Court Judge John J. Sirica temporarily blocked NIH from approving such experiments because an NIH advisory committee had recommended approval of one experiment without conducting a sufficient review of its environmental effects.

The experiment involved a microbe genetically engineered to inhibit the growth of frost on potatoes. Another proposed experiment involved a field test of a disease-resistant, genetically altered plant. Rifkin's petition argued that both are "pesticides" and should be regulated by EPA under the Federal Insecticide, Fungicide and Rodenticide Act.

EPA said its office of pesticide programs would require notification before any release of the anti-frost microbe, but said "it is unlikely" that the plant would be treated as a pesticide.

Rifkin said yesterday that the EPA response "recognizes the potential risk to the environment of introducing a genetically altered organism" and "the need of a government agency to regulate" releases.

He said, however, that the plant should be treated as a pesticide because it is genetically engineered to resist disease-carrying microbes. "In the past, a pesticide was a spray. Now a pesticide can be a piece of genetic information imprinted on a plant," he said.

Rifkin said details of the EPA letter need to be clarified, but that it shows the agency will begin regulating the area before a final policy is formally established.