Washington state banned the sale of vapor products containing vitamin E acetate a compound that federal health officials have identified as a possible cause of a vaping-related illness, according to The Seattle Times.

Vitamin E acetate is an oil that can also be found in foods, dietary supplements and cosmetic products. It isn’t known to cause harm when used in those products but previous research has shown it can interfere with lung functions when inhaled, according to the Centers for Disease Control and Prevention (CDC).

The state Board of Health’s ban follows findings released this month by the CDC linking the compound to the outbreak of lung injuries.

In Washington, where there have been 15 confirmed cases since April, health officials adopted an emergency rule banning the sale of flavored vapor products in October. The rule was recently extended to include the ban of products containing vitamin E acetate.

“While we still need more research to identify a definitive cause, the evidence we have linking vitamin E acetate to the outbreak demands immediate action to protect the public’s health,” Washington Secretary of Health John Wiesman said in a statement.