Accidental discharge of oil during bunkering does not take the ship out of business. But if the response after the spill is not correct, it would definately have the potential to not only take that particular vessel but the entire company out of the business.
In this case the first priority is to contain the spill onboard and to clean up the spilled oil into the sea.
While the spill onboard is contained & cleaned by the ship staff, the oil in the sea is cleaned by the shore clean up parties.
In US, this is done by OSRO (Oil spill response organisation) and in China this is done by SPRO which are contracted by the company as per the local requirements.
So in US, master just need to inform the QI (Qualified Individual) and in China to the SPRO contact and they will take care of the clean up operation for the oil spilled to the sea.
Master also need to inform to the port suthorities (e.g. Harbour Master) through agent.
Master may have to call the P&I club after discussion with the company.
After the investigation from the port and clearance to resume the bunkering operation, the bunkering can be completed and vessel can resume its voyage.
Now where do superintendent's actions fit in all this?
On receiving the call from master about spill of bunker into the sea, the first thing superintendent need to do is to calm down the Master who would most likely be under extreme stress.
Start by asking, "is anyone hurt or are everyone safe"? After taking a brief of the situation, ask the master to send the Initial Situation report (usually company form or in US as per VRP).
Superintendent then need to set up emergency response team in the office as per the company procedures.
Next ensure that Master has informed the required parties such as QI in US or SPRO in China. For other countries Superintendent may need to arrange the spill clean up company for the clean up operation.
If not forwarded by Master, Superintendent need to formward the initial situation report to the vessel's owners / Charterers.
Superintendent need to instruct Master to contact the P&I club (if required) for arranging a surveyor as there may be claims of short bunker supplied.
In short, the job of the superintendent would be to coordinate the notification process to all the third parties and arrange the clean up party if it is not contracted as per the local requirements.
Once the clean up operation is complete both onboard and oil spill at sea, Superintendent need to start the incident investigation to find out the root cause, corrective actions and preventive actions for the incident.