how is isoprene or rubber disposed of in Goodyear and environment?

Answer 1

Typically, old rubber tires get burned in a special incinerator that is unusually hot so it can combust that compound. In some instances, I have heard of rubber being pulverized and remixed with some other products to make an unusually resilient form of roadway that LOOKS like asphalt or blacktop paving, but isn't.

Sadly, sometimes some dumb schmucks just DUMP their old isoprene tires in rural areas that really aren't dumping grounds. But the schmucks don't care.