The rocket released huge amounts of dihydrogen-monoxide. Methane and liquid oxygen burning. *
* Dihydrogen-monoxide is water, the methane is natural gas.
Very clean rocket burning but very powerful. Knocked out a 30' x about 50' concrete slab under the launch mount as well as dug a hole in the ground. It did not have a flame trench like Saturn V nor a water suppression system that Saturn V had. Musk is now going to install those. May take 2-4 months of work to rebuild the base of the launch mount. He already has 2-3 more rockets built to try out.