(CNN) — An investigation into the link between vaping and severe lung illnesses has yielded the discovery of extremely high levels of the chemical vitamin E acetate in nearly all cannabis-containing vaping products that were analyzed, New York health officials said Thursday.

At least one vape product containing this chemical has been linked to each person who fell ill and submitted a product for testing in the state.

Laboratory tests conducted at the New York Department of Health's Wadsworth Center in Albany showed "very high levels" of vitamin E acetate in the cannabis-containing samples, the state health department announced.

Vitamin E acetate is now "a key focus" of the department's investigation into the illnesses, the department said. Some of the products that have been found to contain vitamin E acetate are candy-flavored vapes.

Vitamin E acetate, which is commonly available as a nutritional supplement, is not an approved additive for New York State Medical Marijuana Program-authorized vape products and was not seen in the nicotine-based products that were tested, according to the department.

"The cases of pulmonary illnesses associated with vaping are continuing to rise across New York State and the country," New York Health Commissioner Dr. Howard Zucker said in a written statement on Thursday.

"We urge the public to be vigilant about any vaping products that they or any family members may be using and to immediately contact their health care provider if they develop any unusual symptoms. In general, vaping of unknown substances is dangerous, and we continue to explore all options to combat this public health issue," he said.

The department noted that vitamin E acetate is not known to cause harm when ingested as a vitamin supplement or applied to the skin, but the department continues to investigate its health effects when inhaled because its oil-like properties could be associated with the symptoms seen in the lung illness cases.