Around 30% by calories of seed oil in many oat milks. Was so surprised when I discovered this. It's in the ingredients list but they never even hint at this anywhere else.
Do I need to be worried about the fact that there’s a lot of seed oil in it?
There is oat milk without any added oils, including Oatly, but you have to specifically look for that version, they're not always easy to find. And it will taste thinner without any fatty component that cows milk has.
Canola oil in particular is ever-present in the US, and unlike other refined plant oils, requires the ultraprocessing to be considered fit for human consumption (you'll never see extra-virgin canola oil on a grocery shelf). Debates about its safety aside, I don't feel the need to give it the benefit of the doubt when I could just eat something that doesn't contain it, and that something would likely be healthier for many other reasons.