How to find out about environmental issue and property used?

[Christopher Gosch]

I'm buying a house in Los Angeles, it's a two units which the front one is a commercial building and it is used to be a gas station before but the gas tank is filled with cement since 1971 and the back unit is a residential 3 bed 1 bath. I'm planing to turn the front unit into a restaurant for rent since the property is surrounding by residential and businesses but I'm wondering about environmental issue, in this case who can I talk to to make sure I can build a restaurant on this property before I made the purchase?