Black rubber o-rings safe for MLT?

So I'm about to jump into my first AG batch. I built bulkheads based on Bobby_M's "No Leak" design posted here but I couldn't find silicone o-rings at any near-by hardware stores. Instead I bought similarly sized black rubber o-rings from the faucet hardware section at Lowes. I'm leak-testing as we speak and so far the design lives up the to name but I wanted to know if those black o-rings are safe for food and can tolerate the temperatures the MLT will hold. Any experience with these things?

Im building a mash tun also using an igloo chest cooler and it has a black rubber o-ring, I plan on using it? i was also curious if it would give off flavors. its probably the same kind that you are talking about

The brand was Danco. They don't have much of an odor and they were next to the faucets which leads me to think they'd be okay. On the other hand, who knows what they are actually made of.