Sales of legal cannabis vape carts have nearly tripled since 2018, largely due to the popularity of live resin and receding fears over vaping-related lung injuries.

Legal weed retailers have sold nearly $2.8 billion worth of vape carts so far this year, according to data from Seattle-based cannabis data firm Headset. This year’s total represents a 172% growth over the $1 billion in vape carts sold back in 2018, and December sales are guaranteed to push this year’s total even higher. The overall market share of vape carts has also grown as well, reaching 23.3% of the entire legal weed market, up from 19.9% in 2018.

Vape sales took a serious nose dive in 2019, following a mysterious outbreak of vaping-related lung illness that sickened thousands and killed hundreds more. Health officials warned the public to steer clear of vapes of all kinds, and many states issued temporary bans on both weed and tobacco vapes. Eventually, researchers discovered that more than 80% of these illnesses could be linked to black market THC vapes, and more specifically to a range of toxic contaminants commonly found in these illicit products.

This news helped legal vape manufacturers regain their footing, and sales began to climb again once states ended their bans and fears over the illness began to fade. And although the fastest market growth was reported immediately after the vape scare ended, the popularity of these products continues to grow. According to a recent report from market research firm The Brightfield Group, the overall market share of vapes has climbed from 22 to 23% in the past six months alone.

“Vape sales have increased year-over-year,” said Jake May, marketing director at Sanctuary Medicinals, a multistate cannabis operator, to MJBizDaily. “Young people like them, but also experienced smokers try them and like them.”

Several retailers are reporting that their most popular vape carts fall into one of two categories: either distillates or live resin carts. “It’s two different customer bases that are buying those cartridges,” Allan Mullen of Cannabis City in Seattle told MJBizDaily. “The distillate cartridges are a specific type of customer—either tourists or people that like really fast highs. They like that peaks and valleys type of high.” Live resin, on the other hand, “has a slower, more gradual high.”

Retailers have also noticed that younger buyers tend to go in for distillates, which often include fruity, artificial flavors prevalent in popular nicotine vape brands. Stoners over the age of 30 often choose live resin or rosin, though, as these products tend to have a more natural cannabis flavor. Some stores have also reported that distillates with higher THC concentrations are becoming their top sellers, while half-gram vape carts are becoming less popular.

“Everyone is looking for a full gram,” said Edwin Maguire, general manager of Premiere Provisions, a legal weed shop in Big Rapids, Michigan, to MJBizDaily. “I actually picture half-grams disappearing, unless it’s for a unique product like live rosin, where it becomes too expensive for that full gram.”