A man suffered life-threatening injuries when a crane collapsed on to a ship at a container port.
Fire crews were called to Southampton Docks, owned by DP World, at Dock Gate 20 in Western Avenue, at 0520 BST.
The crane, a twin boom rig with the cab suspended on rails, toppled on to the ship, NYK Themis, the coastguard said.
It is the second serious incident involving crane operations this year and the Unite union said it has "deepened concerns" over worker safety.
Matt Tipper, Unite regional industrial organiser, said the injured man was one of its members.
Legs crushed
"We are obviously concerned over the health and safety implications for the workers there," Mr Tipper said.
"This is of paramount importance to us and we will fully assist in the Health and Safety Executive investigation also providing full support to our member and his family at this very worrying time for them in everyway we can."
DP World said the cause of the incident was being investigated.
The man, whose legs were crushed, was flown to hospital after being airlifted from the scene by a coastguard helicopter.

Hampshire police said the injured man - thought to be in his 30s - was being treated at Southampton General Hospital.
The Health and Safety Executive has been notified and are investigating.
DP World, based in Dubai, is the majority shareholder in Southampton docks, which it owns jointly with Associated British Ports.
A DP World spokesman said: "[The crash] involved the collapse of the boom of one of the quay gantry cranes during the normal operation of loading containers on to a vessel.
"It is too early to determine the cause of the incident, we will of course, be working co-operatively with the Health and Safety Executive and an independent investigation will be undertaken."
DP World Southampton is thought to be the second largest container terminal in the UK.
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Health and Safety Executive
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