MLT Cooler conversion question!

I am converting my coleman 5 gallon beverage cooler into an MLT, and im not sure about some of the equipment im using that will be going inside the cooler.

To create some good seals between the stainless steel washer and the inside wall of the cooler and the s.s. washer and the barb, im using a couple of rubber washers. One is a black rubber faucet washer and the other is a red garden hose washer. The packaging for both did not say anything about heat resistance. Does anybody know if these will withstand mashing temperatures, and if there are any health risks?

They should be just fine. Almost any washer typically used for water lines, hoses, faucets, etc. are going to be fine in terms of health concerns. And most rubber will hold up just fine to mashing temps. You should be good to go as long as you don't have any leaks.

It would be a good idea to let them sit in some hot water, then taste the water. It might not fall apart in the mash but it may taint the flavor.