A 35 year old man remains in a critical condition in hospital after being hit in the head while working at the Forrestfield-Airport tunnel link site.
The man was hit by a construction bracket that had been removed from a wall to undergo routine maintenance yesterday afternoon.
Emergency crews found the man lying unconscious at the scene 20 metres underground with injuries to his face and body.
He was rushed to to Royal Perth Hospital in a critical condition.
The incident occurred in a cavity that will form part of the airport's new train station.
WorkSafe will investigate the matter.
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