Burnt down garage, a Marijuana grow operation, next steps?

[Kitty Horeis]

Hi,

We are buying a wholesale home and just found out the half-burned garage was a marijuana grow operation. The wholesalers said that they did not know what caused the fire and it was one of those first-come, first-served situations.  We are novices and we bit the bait.  

We found out today because someone had broken the door down that it was a marijuana grow operation. My husband said, it is fine, we will just tear it down the garage, because they were just growing a plant.  I googled it  and there is actually a fair bit of chemicals used in this process.  Anyone ever have a situation like this?  All items were left in garage. Does it cost extra to throw in a dumpster? Is it safe for us?  

Any help for some novices, that are probably in over our heads,  would be appreciated!