The real issue IMO is getting a tire with enough capacity to handle the weight period. If your trailer has the clearance for LT tires fine, if it doesn't then getting a ST tire that can handle the load and is constructed decently (think Maxxis) is the trick. If you run your tires with no reserve capacity it doesn't take much to send them over the point of no return. All due respect to those speculating about what caused a blowout, you really don't know short of the training required to make those judgments and having the tire in front of you to examine. I trust the OP gets compensated for the damage and I am pleased no one was injured.