My father past away June 12,2004 and the house I was living in is in my name but the gas bill is in his name. I gas company shut the gas off in January 2006 and now that I want to move back in the house, I went to the gas company and I was informed that I have to pay the old bill first before they will turn the gas back on.
Am I responsible for paying my father's debt, even though I have supplied them with a death certificate and the house is not in his name?

Did you inform them of his death at the time?

This is an iffy one. Even though the account was in his name, the property was in yours. Plus if you did not inform them of his death or request the gas be shut off you were remiss. Obviously some gas was used from June 04 to Jan 06. So, I think you may have to pony up.

Yes, and after they got their lawyers involved, sending court papers to the house, I sent another copy of the death certificate.
Thanks for the input

Yes what? If you sent a copy of the death certificate shortly after he died, then it's their fault they didn't shut off the gas and you don't owe them anything.