https://sci-hub.tw/10.1071/AN15576 page 6 They're citing prior research showing declining efficiency of bromochloromethane additives "due to ruminal flow" while not observing that in their research using seaweed. But it's a bit of an apples to oranges comparison since one was an in vivo and the other an in vitro study. So I may have overstated the impact.

> A quick search doesn't show it as a greenhouse gas. It can deplete stratospheric ozone, but it is very short lived in the atmosphere.

Looks like you're right, I must have confused it with some other bromide.