New London — The Coast Guard is investigating the alleged use of the synthetic marijuana known as "Spice" at the Coast Guard Academy.

The Coast Guard Investigative Service and the academy's police office are looking into allegations that 10 to 20 cadets used Spice this fall, David M. Santos, the academy's communications director confirmed Monday.

The military prohibits its personnel from using or possessing substances that produce psychoactive effects. The U.S. Naval Academy and the Air Force Academy have expelled students for using Spice and the military's leaders have expressed concern over the rising number of incidents of designer-drug usage.

This is the first time cadets at the Coast Guard Academy could face punishment for using Spice.

The Navy said in February that five to 10 people were caught using or possessing Spice in the past year at the Naval Submarine Base and submarine school in Groton. All had to leave the service.

A spokesman said Monday that the base has had no new cases since that time. Information was unavailable on the submarine school.

For years anyone over 18 was able to legally purchase synthetic cannabis products that mimic the effects of marijuana and other compounds that mimic narcotics in the United States, but many states have acted recently to ban them. The House of Representatives voted last week to ban these synthetic drugs.

The investigation at the Coast Guard Academy is the first drug-related inquiry since the summer of 2009, when an investigation into drug use by cadets led to nine sophomore cadets being expelled for using or possessing cocaine or marijuana, Santos said.

Santos said it is too soon to say whether Spice is a problem at the academy.

He also could not say what the potential punishment could be since the investigation is ongoing.

The federal Drug Enforcement Administration issued an emergency ban of five chemicals found in synthetic designer drugs in March for at least a year, with the possibility of a six-month extension, while it investigates the potential danger to public health. These chemicals have not been approved by the FDA for human consumption and there is no oversight of the manufacturing process, according to the DEA.

The House bill would extend the ban to three years. The Senate has yet to take up a similar bill.

j.mcdermott@theday.com