Lambton OPP say the westbound lanes of the 402 east of London Line were being impacted by a garbage transport truck rollover Saturday.
Police said Saturday morning that the passing lane would be closed by the transport ministry to allow for cleanup and removal of the truck from the median.
OPP cautioned that all westbound lanes might be closed at some point and that the cleanup could last all day.
Further information about the crash was not immediately available.