FORT LAUDERDALE, Fla. — The United States Coast Guard seized cocaine with an estimated street value of around $500 million during a series of interdictions in international waters.

The 18.5 tons (16.7 metric tons) of cocaine was unloaded at Port Everglades in Fort Lauderdale Thursday.

In a news release, Coast Guard officials said they worked with other U.S. agencies and law enforcement from other countries to seize the drugs from 15 smuggling boats off the coasts of Mexico, Central and South America.

The operation also led to the arrests of 49 people who will be prosecuted in South Florida.

Capt. Jeffrey Randall tells the Miami Herald the volume of cocaine being smuggled by water is draining the Coast Guard’s resources. In 2017, the agency seized 226 tons of cocaine and brought in 708 suspects.