Work package 3 focused on the physical-chemical characterisation of low-sulphur fuel oils to understand how they behave when released into marine and freshwater environments and to support the development of operational guidelines and weathering models.
The work confirmed large variations between LSFOs, with pour point emerging as a key factor influencing their behaviour. At 5°C, some LSFOs formed compact slicks while others broke into small granular particles that could evolve into viscous slicks or tarballs; at 25°C, they behaved more like conventional oils, spreading and emulsifying over time, though tarball formation was still possible.
The project also reinforced that chemical dispersants have limited effectiveness on LSFOs due to their high viscosity.