I have a joint checking account with my father, when he dies could I be held responsible for his credit card debt

You will not be responsible for his debt by way of the checking account. There may be other concerns to address when contemplating his death. Contact a good probate attorney ASAP.

If your information was not used to obtain those credit card accounts you shouldn't worry about being liable for that debt. However, credit holder may still place/request a lien against your father's estate which would ultimately, and probably, affect your claims for inheritance as well.