WASHINGTON — State and federal health officials investigating mysterious lung illnesses linked to vaping have found the same chemical in samples of marijuana products used by people sickened in different parts of the country and who used different brands of products in recent weeks.

The chemical is an oil derived from vitamin E. Investigators at the U.S. Food and Drug Administration found the oil in cannabis products in samples collected from patients who fell ill across the United States. FDA officials shared that information with state health officials during a telephone briefing this week, according to several officials who took part in the call.

That same chemical was also found in nearly all cannabis samples from patients who fell ill in New York in recent weeks, a state health department spokeswoman said.

Vitamin E is found naturally in certain foods, such as canola oil, olive oil and almonds. The oil derived from the vitamin, known as vitamin E acetate, is commonly available as a nutritional supplement and is used in topical skin treatments. It is not known to cause harm when ingested as a vitamin supplement or applied to the skin. Its name sounds harmless, experts said, but its molecular structure could make it hazardous when inhaled. Its oil-like properties could be associated with the kinds of respiratory symptoms that many patients have reported: cough, shortness of breath and chest pain, officials said.

"We knew from earlier testing by New York that they had found vitamin E acetate, but to have FDA talk about it from their overall testing plan, that was the most remarkable thing that we heard," said one official who took part in the briefing but was not authorized to speak publicly.

The FDA also told state officials Wednesday that its lab tests found nothing unusual in nicotine products that had been collected from sick patients, according to another person who took part in the call.

State health departments are reporting new cases weekly. As of Aug. 27, there were 215 possible cases reported by 25 states. Additional reports of lung illnesses are under investigation, according to the Centers for Disease Control and Prevention, which is leading the investigation.

On Wednesday, Oregon health authorities said a middle-aged adult who died in late July of a severe respiratory illness had used an e-cigarette containing marijuana oil purchased from a legal dispensary. It's the second death linked to vaping nationwide and the first to be linked to a product bought at a store. Illinois officials reported the first death last week. They did not specify what kind of product was used in that case.

State and federal health authorities have said they are focusing on the role of contaminants or counterfeit substances as a likely cause of vaping-related lung illnesses. Many patients have told officials and clinicians that they bought cannabis products off the street. Many of those who have fallen ill say they have vaped products containing marijuana, but some also used traditional nicotine e-cigarettes. 

The Ohio Department of Health said Wednesday that three cases of a pulmonary illness related to vaping have been confirmed in the state. Another 11 cases are under investigation.

Authorities said they are not ruling out adulterants in nicotine vaping products.

Although the discovery of a common chemical in lab tests from the FDA and New York's highly regarded Wadsworth Center lab offers a potential lead, officials cautioned that they are a long way from understanding what exactly is making so many people sick.

An FDA spokesman said the agency is "looking into potential leads regarding any particular constituent or compound that may be at issue."