A student at MIT claimed he synthesized one of the world’s deadliest chemicals last week — sparking a massive hazmat response and the closure of the lab where he worked. The unidentified grad student arrived at a local emergency room, saying he had synthesized dimethyl mercury, a highly toxic compound that can be fatal if exposed to humans in even the smallest amounts, NBC Boston reported. The student was not authorized to be working with the compound and it was not part of his research, according to school officials. MIT closed off Building 18 where the experiment took place on...