Police say three constables were taken to hospital as a precaution Wednesday after coming into contact with an unknown substance at Hamilton's John Sopinka Courthouse.
They say the courthouse constables came in contact with the substance in two unrelated incidents.
Investigators say a man arrived at the courthouse shortly before noon and, during a routine search, was found to have an unknown substance.
At the same time, another man was taken into custody at the courthouse and an unknown substance was found during a search in the courthouse cells area.
As a precaution, the officers who had interacted with the men were taken to hospital, where they were cleared medically and released.
Police say no charges have been laid and they continue to investigate.