Dutch vessels firm Ballast Nedam, developer and Wpd and recruitment company Apro Wind jointly launched an investigation after a man had to be airlifted from the Svanen installation vessel to hospital on 7 July.
The companies have now issued a safety alert focussed on avoiding complacency on high-risk activities by increasing the involvement of personnel in assessing project risk.
They said they are also placing greater emphasis on the roles and responsibilities of workers while high risk activities are taking place. Employees will be reminded of their duties at the start of each shift.
These measures have already been put in place at the Amrumbank West project, where Ballast Nedam is installing monopiles, with immediate affect.
The injured worker, a Danish national, spent six weeks in hospital. He will require further surgery and faces a lengthy recovery period, Ballast said.
He was injured after an emergency towing line became trapped under the Svanen vessel, resulting in a wire snapping and hitting the worker.
Monopile installation at Butendiek was resumed three days after the incident and completed two weeks later.