brothers jeremy dagget and brandon belk worked for a company called badlands power fuels cleaning the inside of frac tanks for around 20 dollars an hour. >> do you know what chemicals have been in that tank? or are you just jumping in and taking a guess? >> no, you're just jumping in. you've got no clue. there should be a msda sheet for every tank that you jump into, a material safety data sheet, which lets you know which chemical is in there and what you gotta do if you're exposed to the chemical. none of those were ever provided. >> what could be in a tank. you're at a place like power fuels, and they're like go clean that tank. what are some of the common things that can be in a tank like that? >> you know, it could be used for storage of oil, it could be used for storage of fresh water. it could be used for storage of salt water, i mean the things that it could be are probably a dozen or more. >> and of all those things, how many of them wouldn't be bad for you to go in and breath? >> i would say clean water. and that would be the only one. i would not go into one of those tanks w