The fish at issue, AquaBounty Technologies' AquAdvantage salmon, is currently classified as a new animal drug for the purposes of FDA review.

The FDA considers any genetically altered animal a new animal drug for approval purposes. The petition calls for the salmon to be classified as a food additive instead, which would require a more rigorous FDA review.

AquaBounty is seeking U.S. approval to market its engineered Atlantic salmon, which contains a gene from another fish species, the Chinook salmon, to help it grow twice as fast as normal.

The consumer groups' petition says the way these salmon are created substantially alters their composition and nutritional value, and so they should be treated as a food additive. Under this standard, they said, the company's data would have to overwhelmingly prove AquAdvantage salmon are safe to eat.

The consumer groups - Food & Water Watch, Consumers Union, and the Center for Food Safety - said in a statement the "new animal drug" designation is insufficient to protect public health. The review process for food additives offers greater protection, they said.

AquaBounty had no comment on the petition.

The FDA did not comment specifically on the petition, but confirmed that the company's application for FDA approval for AquAdvantage salmon is under review, and that genetically engineered animals are evaluated under the new animal drug provisions of U.S. law.

AquaBounty has said in the past that it sees these genetically modified salmon as a potential solution to environmental concerns associated with salmon aquaculture, and discounted fears they might accidentally escape into the wild and affect other fish.

However, Food & Water Watch Executive Director Wenonah Hauter said the company's own study showed that genetically engineered salmon may contain increased levels of a hormone linked to breast, colon, prostate and lung cancer.

The petitioners said a proper review would require genetically engineered salmon to go through comprehensive toxicological studies to ensure the fish are safe to consume and properly labeled.

If approved, AquAdvantage would be the first genetically altered animal for human consumption in the United States.

Genetically modified vegetables such as corn have long been on the U.S. market, and the FDA allows modified animals as pets or to help produce biologic medicines.

There is no timeline for an FDA decision. As a matter of policy, the FDA does not comment on citizen petitions.

(Reporting By Deborah Zabarenko, Environment Correspondent; Editing by Todd Eastham)

This story updates clarifies the sixth paragraph reference to new animal drug

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