All lanes of eastbound Highway 401 remain closed at Winston Churchill Boulevard after a major collision early Thursday morning, and will not reopen until the evening.

The accident happened around 12 a.m. when a tractor-trailer slammed into a truck protecting road workers, who were cleaning up a diesel spill from an earlier accident.

A worker on the road was seriously hurt in the crash and taken to Sunnybrook hospital with unknown injuries.

The driver of the transport truck was also rushed to hospital with serious but non life-threatening injuries, and he faces careless driving charges.

Despite crews putting sand down and sweeping, the lanes remained too slippery to drive on for morning commuters. Crews were forced to re-pave and repaint the lanes before they could re-open to traffic.

The OPP told 680News motorists can expect that stretch of highway to be closed until at least 5 p.m., Thursday.