Father works in heating and cooling industry on daily bassis he comes into contact with many toxic chemicals could he expose us to harmfull ammount to?

Depends which chemic: als that he is exposed to. He should shower and leave boots and soiled clothes in a plastic bag away from contact with bed linens, clean clothes using general decontamination procedures. If he wears protective clothing at work over his normal clothes, or in place of them, then this may not be needed. Depends on whether he's inhaling fumes or not. Urine samples can show how much he's absorbing.