Think you’ve been exposed to toxic chemicals on the job? Hand over your hair. A new DNA testing technique can help verify or refute claims of workplace poisoning by exposing a healthy person’s DNA to the chemical in question to see how the genes are affected, then comparing to the employee’s DNA. It seems like nary a day goes by without someone suing their employer over chemical exposure, and until now, strong evidence was often hard to come by. The new technique, while expensive, has already been used in more than 20 cases in California, leading to victories for both employees and employers.