First, it’s not entirely clear whether FDA can decline to approve a drug based on environmental concerns. The Food Drug and Cosmetic Act instructs FDA to consider the safety of veterinary drugs, but here’s how it defines safety:

“In determining whether such drug is safe for use under the conditions prescribed, recommended, or suggested in the proposed labeling thereof, the Secretary shall consider, among other relevant factors, (A) the probable consumption of such drug and of any substance formed in or on food because of the use of such drug, (B) the cumulative effect on man or animal of such drug, taking into account any chemically or pharmacologically related substance, (C) safety factors which in the opinion of experts, qualified by scientific training and experience to evaluate the safety of such drugs, are appropriate for the use of animal experimentation data, and (D) whether the conditions of use prescribed, recommended, or suggested in the proposed labeling are reasonably certain to be followed in practice.”

So it’s clear that FDA can refuse to approve a drug that harms the animal or the people who eat the animal. (If you were wondering what they did to ensure that level of safety, here’s the agency’s explanation.) But environmental damage? Much less clear; expect to hear a lot of discussion of “among other relevant factors” as the case proceeds.

The fact is that FDA already has considered at least some environmental factors in approving the AquaBounty salmon–for example, it requires that the fish be raised in land-based facilities to make it difficult for fish to escape and mingle with wild salmon populations. (AquaBounty already has taken the step of sequestering the small cohort of male fish it needs for egg production and sterilizing its fish intended for food, which are all females.) The question is whether the agency can decline to approve a product based on environmental concerns and, if so, what standards would apply. One potential glitch as the trial moves forward: A judge could rule that FDA has no authority to make decisions based on environmental impact and no ability to impose conditions on companies whose products may be environmentally harmful but safe under the terms of the FDCA. Who would be in charge then? It’s not clear, but the answer might be “nobody.”

But that’s another day’s concern. For the moment, barring the possibility that a higher court reverses Chhabria, FDA has the right to regulate genetically altered animals under its pathway for veterinary drugs, the rest of the suit will continue, and a batch of AquAdvantage salmon continue to fatten up down in Indiana.

They may have thought that being raised in a tank meant they didn’t have to swim upstream against raging currents. They were wrong.