Around 6,000 pounds of paint spilled near Highway 402 after a commercial truck rolled over Thursday morning.
Middlesex OPP said it happened on the eastbound lanes near Centre Road just before 5:40 a.m.
The driver was transported to hospital with non-life threatening injuries.
The Environment Ministry has been notified and is investigating.
The roadway was down to a single lane in the area for clean-up but has since re-opened.
Police continue to investigate the cause of the collision.