RICHMOND (CBS SF) — Caltrans and CHP are reporting an accident on the Richmond-San Rafael Bridge that has closed eastbound lanes of the span.

Caltrans tweeted about the accident shortly before 2 p.m., stating that a crane was involved in the crash that blocked the left lane.

A second tweet stated that an overloaded truck had hit a maintenance scaffold on the bottom of the upper deck.

Caltrans officials later clarified that an excavator being towed by a truck struck a beam on the bridge. Officials are completing an inspection of the beam, which is occupying the left lane of the roadway.

Motorists are advised to expect delays and to use alternate routes to avoid the area. There is no estimated time to reopen the roadway.