A bill to increase the amount of marijuana a person can possess before facing stiff criminal penalties failed 15-9 in the Hawaii Senate on Monday.

It was the second defeat of a measure at the Legislature this session to allow more people to possess pot. A bill to allow recreational use of marijuana for people 21 years and older died earlier this month.

The reasons for shelving Senate Bill 2487, the decriminalization measure, were similar to Senate Bill 3335, the recreational marijuana bill. Opponents said more marijuana would end up in the hands of youth, it would discourage Asian tourists from visiting, it would not stop black market sales and it would lead to more automobile accidents.

Passage of the bill would send a message “to our keiki and the community that this drug is harmless — it is not,” said Sen. Sharon Moriwaki, whose district includes Waikiki. “It is a threat to our No. 1 industry, tourism.”

Even though medical marijuana is legal in Hawaii and nearly half of all states have moved to legalize the drug, Moriwaki said marijuana is a public health threat.

“In fact, as more data come in, we learn cannabis is even more dangerous to the public health and safety than tobacco or alcohol use,” she said. That is in part because marijuana today has a higher THC content and is often laced with other drugs, she said.