The death toll in the United States from the mysterious vaping-related illness rose to 17 on Oct 2 with 805 confirmed and probable cases of the illness, as per the U.S. Centers for Disease Control and Prevention (CDC).

The number of fatalities linked to the use of e-cigarettes and their flavored or marijuana pods is rising despite loud warnings from U.S. health and government authorities that young people and young adults stop vaping amid the growing crisis.

On Aug. 23, the number of "vaping-associated acute lung injury" or "vaping-linked lung disease" cases amounted to only 31 confirmed cases with one death. The first known death from this illness was reported in Illinois. The number of confirmed cases rose to 200 the following week in at least 22 states.

Common symptoms of vaping-associated acute lung injury reported at the time include difficulty in breathing, shortness of breath and chest pain. Some patients have also reported fever, cough, vomiting and diarrhea.

CDC believes many of the cases are related to THC, the compound in marijuana that causes the euphoric high associated with marijuana use. Other health experts point to a vitamin E chemical in flavored e-cig pods as partly responsible for the outbreak of vaping-linked lung disease.

The rising number of hospitalizations has allowed doctors to better understand this still mysterious illness. It has also allowed doctors to better understand the effects of vaping on the lungs and the human body, in general.

Now, the latest tests seem to confirm that toxic chemical burns could be the cause of hundreds of vaping-linked lung disease cases across the United States. New images of lung tissue taken from people who got sick after vaping were published Wednesday in the New England Journal of Medicine.

The disturbing images revealed lung tissue showing severe chemical injuries caused by vaping unknown substances. The study said these injuries look like the kind people normally see when a person is exposed to spilled toxic chemicals.

"It looks like the kind of injury that we normally see when a person is exposed to a spilled drum of toxic chemicals at their workplace," Dr. Brandon Larsen, an author of the study and a surgical pathologist at the Mayo Clinic in Arizona, said.

Dr. Larsen and his team are often asked to examine lung tissue for a second opinion, or in cases bewildering other doctors.

In one image, a cross section of a small airway showed a pink circular structure in the airway wall. Pathologists asserted there shouldn't be anything in the middle of that structure so air can flow easily. Instead, the image showed widespread inflammation and injury that restricts oxygen flow.

Experts are concerned about youth-directed marketing of e-cigarettes and flavors, linking it to an increase in their use and appeal among adolescents. Erik Odiin/Unsplash