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.

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

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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.

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