"This is by far the largest operation we have ever carried out against the production and distribution of synthetic drugs," said Andy Kraag, head of Europol's Serious Organised Crime Centre, in an interview with AFP.
Around 1,000 tons of chemicals – used to manufacture street drugs such as MDMA, amphetamine and methamphetamine – have been seized.
Over 85 people have been arrested, including the two suspected ringleaders, both from Poland.
The year-long operation has involved police officers from Belgium, the Czech Republic, Germany, the Netherlands, Poland and Spain.
"This is a massive blow to organised criminal groups involved in drug trafficking," Kraag said.
