The US Centers for Disease Control and Prevention (CDC) is investigating lung illnesses that may be linked to e-cigarette use in several states across the country, according to a statement.

The CDC said that 94 possible cases of severe lung illness associated with vaping were reported in 14 states from June 28 to August 15, including 30 cases in Wisconsin.

CDC is now providing consultation to the departments of health in Wisconsin, Illinois, California, Indiana, and Minnesota about pulmonary illnesses linked to e-cigarette product use, primarily among adolescents and young adults.

Additional states have alerted the CDC to possible cases and investigations into these cases are ongoing.

There is no conclusive evidence that an infectious disease is causing the illnesses. While some cases in each of the states are similar and appear to be linked to e-cigarette product use, more information is needed to determine what is causing the illnesses, according to the statement from the CDC.