The New York State Department of Health shared photos of some of the products it found to contain vitamin E acetate, a key focus of the department's investigation into potential causes of vaping-associated lung disease.

THC, or the compound that produces a high in marijuana, was used by patients in most of the cases, CDC Principal Deputy Director Anne Schuchat told reporters Friday. However, health officials still do not know what specific chemical is making people sick.

The vaping-related illness has sickened 805 people across 46 states and one territory, the CDC said Friday. One person died in Oregon this week, bringing the death toll from the disease to at least 13; a new death in North Carolina also may have been related.

The Centers for Disease Control and Prevention is urging people to stop vaping THC products as the death toll from a mysterious lung disease rises with no signs of abating.

"Of the patients who reported what products they used, THC-containing products were the most prominent link across patients, with only 16% reporting using only nicotine-containing products," Schuchat said.

Among the 514 cases where the CDC has data on which substance they were vaping, 76.9% said they used THC and 56.8% reported using nicotine, according to a CDC report published Friday. More than a third of the patients, 36%, said they exclusively used THC while 16% said they only vaped nicotine.

Illinois and Wisconsin officials said they found Dank Vapes was the most commonly used brand of pre-filled THC cartridges in those states, according to a separate report also published Friday. Of the 86 patients interviewed, 57 said they used Dank Vapes products.

Officials said "Dank Vapes "appears to be the most prominent in a class of largely counterfeit brands, with common packaging that is easily available online and that is used by distributors to market THC-containing cartridges with no obvious centralized production or distribution."

While the investigation appears to be narrowing, the CDC still does not know what substances in the products is causing the problem, Schuchat said.

"We have many questions about the supply chain and the integrity of these products," she said. "So I think that we need to have an open mind and learn a lot more about the supply chain, as well as about the contents of various products that are used within e-cigarettes or vaping to understand which of many toxins might be leading to this type of lung injury.

You know, to have over 800 cases in this short period of time, many leading to intensive care unit hospitalizations and potentially longer term lung damage, we really need to understand how many different kinds of products could be risky and how to stop their distribution," she said.

The illness is primarily hitting young men. Among the 805 patients, 69% were men and 62% were ages 18 to 34, the CDC said. The median age is 23.

The CDC is urging people to avoid vaping, particularly THC, until it's determined what's making people sick.

"We do not know yet what exactly is making people sick," Schuchat said. "For example, whether particular solvents or adulterants are leading to lung injury, or whether cases lead to a single supplier or multiple ones."