From what I can tell, this person is running a scam. He promised to get rid of the mold in my basement and hvac system, indeed the whole house for an amount of $ 6k. In his words (more or less), see everything has to breathe, 48 hours of chlorine dioxide poisoning will kill the mold everywhere in your house." As a new home owner I did not know better and saw it as a good deal. We would have to be out for two days On the morning, he came with a contract requiring I pay him $3k in the beginning of the process, $3k after two days when the process would be complete. I saw it as rushed, but agreed and signed. He brought in a few large cooking pots, boiled water in it in my house, and added chemicals to that ... He had a couple of box fans to bow air on that. In less than an hour, he was done... and waiting for the money in his car. Two days later, he brought his son and wife who wiped off the mold in a couple of places-- using bleach which is a completely wrong product to use on wood-- and in less than two hours... he said he was done. He insisted that the mold was DEAD --I do not think, I KNOW it is dead, and the cleaning is just for cosmetic purposes. Meanwhile, suspecting something was off, i had told him I would need to test before I pay him the full amount, yet I paid him another $1500. He texted me after two weeks saying there was still some mold in the basement, "not dangerous but it is there". I sad alright he could try again. he did the same process one more time -- only in the basement and with a higher concentration. For two days, we had to look for lodging for ourselves and our cats. He said he had taken the samples and will send them for testing. When I cam back, I took my own tests -- found out, even lab tests are very simple and inexpensive, not the $300 he had told me -- and well, there is mold in the basement, and in the ducts. in addition, all the ducts and nails in my basement are corroded and dripping. I called him multiple times and he would not pick up my phone. He responds to the texts once in a while, saying that he has "new materials" and "completely different method" and he is committed to taking care of it. It is obvious that the gas will not kill the mold, it will only destroy my house by corroding the nails and pipes. he refuses to tell me what the different method is; i insisted he had to pay if we were going to have to leave our house yet another time. He would not agree.... nor would he give me any more detail, and her does not pick my phone anymore. I am convinced, he can only damage my house; neither the chlorine dioxide nor the bleach he sprays on the wood will get rid of the mold. It is $4500 down the drain, in fact worse, since there is so much corrosion in the basement.