Bunkering may be a routine operation, but it involves high risk. According to Gard, there are two main concerns in bunker spills:

  1. Environmental impact of spills, especially from persistent oils;
  2. Risk of crew members and/or owners facing criminal prosecution.


There can be numerous reasons for the spills, but overflow incidents account for the majority of bunker spills. The underlying causes could be a high flow rate, wrong line up, improper monitoring of both the tanks being bunkered and those not being bunkered, or not acting on high level alarms.

What is more, the human element is very much involved. Bunker procedures and checklists usually include all the necessary points to prevent such incidents from happening, but what is lacking is applying them.

However, Gard adds that continuous monitoring of bunker tanks irrespective of whether they are being filled or not can help prevent a spillage, even in cases of incorrect line up. For this reason, it is important that crew members who have been assigned to manage a bunkering operation, are not burdened with other tasks and are well rested so that they can focus on following what is required by their procedures.