Windsor police, fire and EMS returned to the scene at Gem Avenue Saturday to investigate a “potential hazardous material.”
The substance was discovered after the Drugs and Gun Unit executed a search warrant at a home in the 2600 block of Gem Ave. on Friday.
HAZMAT trucks were also on hand Saturday.
Police told CTV News Friday there was no direct threat to the public.
"We made sure no one else was in the residence and evacuated the residence," said Sergeant Steve Betteridge. "Neighbours know what's going on, we've gone door to door we've been able to speak with them.”
Investigators would not provide more details about the scene on Saturday as they searched in and around the home. They also declined to comment on who lives in the home, or whether any arrests were made.
Some neighbours who declined to appear on camera suggest the house is known to be a drug lab.
Police say more details about the case will be released on Monday.
The last time a hazmat team surrounded a home in Windsor was in June on Dougall Ave. where a resident died from a carfentanil overdose.