Dasm. Very bad stuff. 🙁
I agree with Danc, several days off should be necessary. 😉
I was working construction back in my HS and early college days, and one time in St. Joe, Mo. a company had a major chlorine gas leak slightly less than half a block down the street from where I was working. It about knocked us for a loop, I couldn't imagine being inside the building when it happened. :Q
We had to go into underground vaults, and we always used the required ventilation to clear out the vault before going down in. It only takes seconds to be overcome, and with some gases you will not know until it's too late. This one looks like it was just a freak accident that they hit a sewer line that released the gas into their trench. 🙁