WASHINGTON, Oct. 4 (Xinhua) -- The U.S. Centers for Disease Control and Prevention (CDC) said Thursday that 1,080 vaping-related lung injury cases have been reported as of October 1 in the United States.
A total of 18 deaths have been confirmed in 15 U.S. states, with more fatalities under investigation, according to the CDC.
"This may be the tip of the iceberg when it comes to the escalating health threat this outbreak poses to the American public, particularly youth and young adults," said Robert Redfield, the CDC director.
Among 578 patients with information on substances used in e-cigarettes 90 days prior to symptom onset, about 78 percent reported using products containing THC, the principal psychoactive compound in marijuana, while 17 percent reported exclusive use of nicotine-containing products, according to the CDC.
The causes of the outbreak is still unclear. A study published on Wednesday showed that vaping-associated lung damages are most likely caused by direct toxicity or tissue damage from noxious chemical fumes. An earlier investigators suggested that vitamin E acetate was found in samples of products handed over by some patients.
The increasing number of vaping-related deaths has alarmed the country. The Food and Drug Administration (FDA) is making a policy that will clear the market of unauthorized, non-tobacco-flavored e-cigarette products.
