Here’s what marijuana researchers have to say about 420 or 'Weed Day'

Marijuana is legalized for recreational use in Canada and 24 U.S. states, two territories and the District of Columbia.

It’s 420 or “Weed Day,” and people around the world will be paying homage to their favorite guilty pleasure: marijuana.

Currently, 24 states, two territories and the District of Columbia in the United States have legalized marijuana for recreational use, making it that much easier for people to take a toke or pop an edible at 4:20 p.m. on April 20 (if not all day).

But not everyone joins in on the 420 festivities. Some scientists who study weed have become increasingly concerned about the potential harm cannabis can do to the body, especially when smoked or vaped.

“When you burn something, whether it is tobacco or cannabis, it creates toxic compounds, carcinogens, and particulate matter that are harmful to health,” Dr. Beth Cohen, professor of medicine at the University of California, San Francisco, told CNN previously via email.

Marijuana smoke may even be more harmful than tobacco because users hold the hot smoke in their lungs longer to maximize their high, Cohen said. A March 2021 study found teens were twice as likely to report “wheezing or whistling” in the chest after vaping marijuana than after smoking cigarettes or using e-cigarettes.

“I’m in Colorado, and on 420 the smoke billows out of places where people gather to celebrate — it’s like a factory smokestack,” said Robert Page II, a professor of clinical pharmacy and physical medicine at the University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences in Aurora.

“I worry when people are in an enclosed space because new data is beginning to show that secondhand marijuana smoke may be just as dangerous as the primary smoke,” Page said. “Like tobacco, cannabis affects the central nervous system, and there are side effects which tend to primarily be cardiovascular in nature.”