Are GMO salmon safe? Really?

Comparison of regular- and fast-growing GMO Atlantic salmon.

Late last month, perhaps lost in all the Christmas hubbub and hullabaloo, the Food and Drug Administration (finally) issued a ruling that AquaAdvantage's/AquaBounty's genetically modified salmon posed little to no threat to the environment. Headlines read (Huffington Post) "GMO salmon not a threat to nature, FDA says" and (PopSci) "GMO salmon environmentally safe". 

But is that really what the FDA said in their ruling? Or is this just the media's take (spin?) on a story to make it a sexier headline?

Here's what the FDA actually said in their ruling - what's known as a Draft Environmental Assessment, more specifically, a Preliminary Finding of No Significant Impact (fondly referred to as a FONSI) - "the proposed action will not significantly affect the physical environment of the United States." (I've excerpted parts of the FONSI, below but you can read it in its entirety)

This is the part that most news organizations clued in on. But that's not the whole story. After all, where there any caveats? And what is meant by "physical environment" or "proposed action"? Turns out, understanding both is significant to understanding the ruling.

And what of potential unintended consequences and compounding effects to the environment and human health? I find it disheartening that the burden of proof for EPA and FDA rulings is the companies do not have to demonstrate that their product will do no harm, rather only that they have some safeguards in place to minimize harm. And no long-term studies are required.

Does this seem like a sensible way to keep people safe - simply trying to minimize potential harm? What if the harm inflicted is quite large? And how do we measure "minimized harm"? Is it just simple economic accounting (e.g., cost/benefit)? I'm not jumping to conclusions about the safety of this fish. By all accounts it's probably very safe to eat. But will it be safe in the environment when (not if) these fish accidentally get out of their holding facilities (and they will, whether by some "act of God" or a human bucket brigade)? The FDA didn't rule on that...only that under the company's current plan of raising these GMO fish outside of the US, there's likely no significant harm to physical environment of the US. Seems like there's an awful lot of "what ifs". As Jerry Seinfeld says to George Constanza in one Seinfeld episode, "that's a pretty big motza ball hanging out there"...and I say too few safeguards!

I'm not sure I'm comfortable with that.