BOSTON — Boston Mayor Martin J. Walsh has signed an ordinance banning the possession, sale (by convenience stores and other retailers), manufacture and distribution of synthetic cannabinoids, also known as K2 or Spice, in Boston.

“I thank the City Council for working on this important measure to better protect our residents from these extremely dangerous substances that are becoming increasingly accessible and more targeted towards our young people,” said Walsh. “This ordinance is another step to create a healthier Boston for today’s youth and future generations.”

The new ordinance will be enforced by the Boston Police Department, which also has authority to promulgate rules and regulations. Fines for violating the ordinance are $300 per incident. Each incident of a violation will constitute a separate offense.

The ordinance is effective immediately.

“As a Boston City Councilor and father of two young children, I am delighted to see the swift passage of an ordinance that will prohibit the distribution and possession of these very dangerous designer drugs that are negatively impacting our communities,” said Frank Baker. “It is my hope that this ordinance will give our law enforcement officials the authority to enforce not just the sale and possession of the synthetic marijuana found in our stores today, but all types of synthetic chemical compounds produced in the future.”

Synthetic cannabinoids are extremely dangerous and are often sold as household products, such as herbal incense. The use of synthetic drugs can have serious side effects that can endanger the health and safety of individuals, such as severe agitation, anxiety, racing heartbeat, higher blood pressure, nausea, vomiting, muscle spasms, seizures, tremors, hallucinations, psychotic episodes and suicidal thoughts and actions.