Otherwise, you would have to put in an offer and perform a sweep of the property yourself to find out.
If you are seriously considering it, you might want to get yourself a buyers agent to represent you though. If you search "dual agency" on this website you will get lots of opinions regarding having the listing agent represent you as your buyers agent, too.
This home does not appear to have an oil tank, it has natural gas. Let me know if you need further assistance.