You need to get a CDL with hazmat endorsement. If you drive a tanker with 1000 gallons you need a Tanker endorsement. If you get on with a company that has a fire contract and you work on T3's they will want you to drive also. You need to negotiate for a wage above your regular mechanic pay if that's what you want. Good luck with that though. You will have to put up with Forest Service mentality however. It's all good if you're thick skinned.