Two more incidents of vaping-related lung injuries have been confirmed in Hawaii, bringing the number of cases to four as the death toll and illnesses nationwide continue to grow.

All of the local patients, including two children, reported vaping tetrahydrocannabinol (THC), the psychoactive ingredient in pakalolo. All were hospitalized, some with symptoms including shortness of breath, gastrointestinal problems, fever and chest pains, and have since recovered. The state Department of Health is investigating at least a half-dozen more lung injury reports.

The DOH is urging residents to stop vaping, regardless of substance or source, until investigations nationwide determine the culprit in the illness.

“Vaping is not safe. Our advice is, basically, do not use e-cigarettes or vaping devices of any kind,” said Health Director Bruce Anderson, adding that there’s likely more people who have become sick from e-cigarettes but haven’t gone to a health care provider. “I’m pretty sure it’s the tip of the iceberg.”

There were 42 deaths and 2,172 confirmed and probable lung injuries associated with vaping in 49 states, the District of Columbia, Puerto Rico and the Virgin Islands as of Wednesday, according to the Centers for Disease Control and Prevention.

Federal and state health officials have detected a synthetic form of vitamin E in some vaping fluids containing THC, though they have not determined the exact cause of injuries and deaths. Other people who have become sick reported using nicotine or a combination of nicotine and THC.

“The public should refrain from using these products, regardless of whether they contain nicotine or THC,” he added. “Those are probably not all that we’re concerned about. There may be other sources that’s also hazardous.”

Health officials are specifically cautioning youth, pregnant women and adults who currently do not use tobacco products to stay away from e-cigarettes. Symptoms can start off vague with a cough, bronchitis or a simple respiratory condition, but become life-threatening.

“They’re much more vulnerable to any agent that might cause adverse health effects, and we simply do not know the long-term health effects of vaping,” Anderson said.

The Health Department will launch a series of prevention programs in 2020 and is considering legislation that would regulate vape shops and potentially ban internet sales and flavored vaping products.

Hawaii ranks second in the nation for e-cigarette use among high school students, with an estimated 25.5% currently vaping, twice the national average, the latest Health Department statistics show. E-cigarettes are even more prevalent on the neighbor islands, with as many as 34% of high school students using the devices.

Lola Irvin, administrator of the DOH Chronic Disease Prevention and Health Promotion Division, said children as young as elementary schoolers have even been caught using the electronic devices that heat liquids containing flavored chemicals and possible toxins including formaldehyde and heavy metals and turns them into vapors that are inhaled.

“This is of grave concern,” she said, adding that the alarming trend is expected to worsen. “We want to ensure our children have the healthiest future possible. They should not start their adult lives with lung injuries that could be prevented.”