The TVA and Jacobs Engineering Group says they will cooperate with a TBI criminal investigation. On December 22, 2008, over 5 million cubic yards of fly ash spilled ion Roane County creating one of the worst environmental disasters in history. TVA hired Jacobs Engineering Group for the cleanup. That was completed in 2015 but several workers fell sick and some died. Allegations surfaced claiming Jacobs Engineering would not let cleanup workers wear protective gear and manipulated air monitoring equipment. Attorneys for Jacobs Engineering say the company nor any employee committed any wrongdoing in the clean-up process. The TBI is now looking into alleged criminal conduct during the cleanup at the request of District Attorney General Russell Johnson.