New York officials on Monday announced plans to strengthen regulations of vaping and e-cigarette products amid heightened public health concerns surrounding the use of the products.

Gov. Andrew Cuomo at a news conference in New York City announced the state Department of Health would investigate companies that produce vaping substances and the materials used in making them.

Health officials will also require shops that sell vaping products to post warnings about their use.

Cuomo once again indicated he will push for a ban on flavored e-cigarettes. He had initially proposed a measure allowing the Department of Health to ban the products earlier this year in his State of the State address in January.

The proposal did not pass by the end of the legislative session in June. Lawmakers earlier this year boosted the minimum age for purchasing tobacco products from 18 to 21.

“It’s attracting thousands of young people to an activity, and again, we don’t know exactly what they are smoking or what the consequences are,” Cuomo said.

“We don’t know what a lot of these substances. If you don’t know what it is that you are smoking, don’t smoke it,” he said.

The proposed ban is in light of reports of vaping use causing illnesses among some, potentially due to a chemical contained in the devices or by mixing the device with THC.

“I don’t think you will get a public health official who will say to you vaping is safe,” Cuomo said.