The amount of liquid marijuana seized in Japan has been surging, putting police and customs authorities on high alert.

The estimated amount of marijuana in liquid form confiscated by Tokyo Customs in 2020 jumped nearly 70 times from the previous year’s level. A customs official described the situation as “an explosive increase.”

The liquid extracted from marijuana plants has a higher content of hallucinogenic tetrahydrocannabinol, or THC, than dried cannabis and can be used in a similar way to electronic cigarettes.

“Many users are youngsters,” an official at Tokyo’s Metropolitan Police Department said. “My impression is that it has been in wider use for the past 10 years or so.”

According to Tokyo Customs, the liquid marijuana seizure amount was roughly 400 grams for the whole of 2019, but it jumped to some 9 kilograms in the first half of 2020 and to 18 kilograms in the following five months through the end of November.

Meanwhile, the amount decreased substantially when it came to cannabis in general, due to fewer passenger and cargo flights amid the novel coronavirus pandemic.

Authorities also said that in many cases last year liquid marijuana was contained in bottles disguised as honey and other products.

“If it is in the form of leaves, it’s easy to detect with X-ray. When it’s in bottles, however, it’s harder to find,” a customs official said.

The official also noted that authorities cannot check all bottles of wine imported from overseas, which are huge in number, and that opening such bottles is not easy.

“Liquid marijuana smells less than the plant version, making it harder to detect,” an MPD official added.

Liquid marijuana-linked arrests have been increasing as well.

In October last year, Saitama prefectural police nabbed a man in his 20s who worked for the Kanto-Shinetsu Regional Taxation Bureau for alleged possession of the liquid at home.

Another MPD official suggested the possibility that bottles of liquid marijuana purchased abroad at low prices are being sold at high prices in the country by smugglers.

“In collaboration with customs and other authorities, we will strengthen our crackdown,” the official said.