No Spill Zone has an excellent explanation of the taxonomy, if you will, of oil spills (although not their effects – which would be an immense task, given variation between marine environments and coastal areas):

Alex Spence, the general manager for Seacor Environment Services Middle East, says that to appreciate the work of companies such as his, it is first necessary to understand how they categorise spills.

“We tend to classify spills into three categories – T1, T2, and T3,” he says.

In broad terms, a Tier 1 spill requires only a local response; Tier 2 might demand regional resources and Tier 3 necessitates international assistance.

“A T1 — that would be your first-strike response,” he says. “That would be like if you have a very small fire in a room, picking up a fire extinguisher and putting it out.”

A T2 is “if the whole room catches fire and you alert the fire brigade – and the T3 is if the whole building catches fire”.

A T2 spill can take anything from a couple of days to a week to deal with; a T3 can take months, or even years.

There are, he says, three response options for dealing with oil spills: monitoring and surveillance for light spills, containment and recovery for larger incidents and a combination of containment and spraying of chemical dispersants for the most severe.

Middle East Oil Spill Classifications

at the No Spill Zone