NEW YORK (CBSNewYork/AP) — More than 500 people have been diagnosed with vaping-related breathing illnesses, but the cause remains unknown, U.S. health officials said Thursday. An eighth death was also reported.

Meanwhile, the Food and Drug Administration revealed that its criminal investigations unit started tracking leads early on, as cases pointed to black market vaping products. The agency’s tobacco director, Mitch Zeller, stressed that it is not interested in prosecuting individuals who use illegal products but is lending a hand because of the unit’s “special skills.”

The Centers for Disease Control and Prevention said 530 confirmed and probable cases have been reported in 38 states and one U.S. territory, up from 380 a week ago.

Missouri joined the list later Thursday, announcing the death this week of a man in his mid-40s at a St. Louis hospital.

MORE: New York Health Officials Vote To Ban Flavored E-Cigarettes After 7th U.S. Death

New York became the first state to ban the sale of flavored e-cigarettes Tuesday, a move that comes as federal health officials investigate a mysterious surge of severe breathing illnesses linked to vaping.

The vote by the state Public Health and Health Planning Council means the ban, which covers all flavored cigarettes and other vaping products except for menthol and tobacco flavors, goes into effect immediately. Retailers will have two weeks to remove merchandise from store shelves.

AT A GLANCE

Canada reported its first case Wednesday, a high school student who was on life support and has since recovered.

All patients had used an electronic cigarette or other vaping device.

Doctors have said the illnesses resemble an inhalation injury, with the lungs apparently reacting to a caustic substance. So far, no single vaping product or ingredient has been linked to the illnesses, though most patients reported vaping THC, the high-producing ingredient in marijuana.

The man who died in Missouri told his family he started vaping in May for chronic pain, but investigators have not yet determined if he was vaping THC, according to a spokeswoman at Mercy Hospital St. Louis.

Watch: What You Need To Know About Vaping-Related Illnesses:

Two-thirds of the cases involved 18 to 34-year-olds. Three-quarters are men.

Some of the first cases appeared in April. CDC hasn’t said when most people got sick.

A congressional subcommittee will hold a hearing on the outbreaks on Tuesday.

(© Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)