The Centers for Disease Control and Prevention has updated and revised the national tally of illnesses linked to the use of e-cigarettes, aka vaping, dropping the count from 450 possible cases to 380 confirmed and probable cases, the agency announced late Thursday.

The new figure follows a clearer clinical definition for the illness as well as further investigation into individual cases. The 380 confirmed and probable cases now span 36 states and still include six deaths, as reported earlier. The CDC added that the current number of cases “is expected to increase as additional cases are classified.”

While health investigators are clearing the air around the clinical aspect of the cases, the cause is still foggy. Though all the cases are associated with vaping, investigators have struggled to identify specific vape products or ingredients that tie all the cases and symptoms together.