Officers seized 37 kilograms of ketamine and arrested eight people after raiding three synthetic drug labs in the GTA late last week, Toronto police announced Wednesday.

Police say they executed 18 search warrants on Friday in an investigation called "Project Apollo."

The alleged drug productions sites were at 80 Colville Rd. in North York; 29 Plumbrook Cres. in Scarborough; and 107 Northolt Cres. in Markham.

Police say they also seized one kilogram of cocaine, 200 grams of MDMA, and 11 grams of heroin, as well as chemicals for producing ketamine, lab equipment and cash.

Eight people were arrested. Police say they appeared in court Tuesday and that three suspects are still at large.​

Officers removed hazardous materials Saturday from this home in Markham, which police allege was the site of a synthetic drug lab. (CBC)

In a news release. police said ketamine is an anesthetic often used in veterinary surgery. It can be used in powder or liquid form and has addictive properties, police say.

Ketamine stops feelings of pain, raises heart rate and blood pressure, and "can produce vivid dreams and a feeling that the mind is separated from the body," the news release said.

The Toronto Police Service says it worked with its drug squad, the Integrated Gun and Gang Task Force, 43 Division Major Crime Unit, Forensic Identification Services, CBRNE, York Regional Police, and the Combined Forces Special Enforcement Unit.