Unexploded Ordnance

Dear constituent,

Thank you for contacting me about the impact of noise from unexploded ordnance (UXO) clearance on vulnerable marine species.

I recognise that ocean noise is one of the many serious man-made threats faced by whales, dolphins and other marine animals. These threats include hunting, ship strikes, chemical pollution, entanglement in fishing gear and issues arising from climate change.

The location and size of many offshore wind farm developments and cable connector projects mean there is a high likelihood of encountering UXO during construction. This is particularly so where there is overlap with World War I and World War II conflict areas, military training areas and munitions disposal sites.

When UXO cannot be avoided or safely removed, explosive ordnance disposal is used which typically involves detonation on-site using high-order detonation. These disposals produce acoustic pulses, which, as you know, can have a number of adverse environmental consequences, one of which is the risk to marine life from exposure to the high sound levels produced.

Two phases of a Department for Business, Energy and Industrial Strategy (BEIS) funded project to characterise and contrast the acoustic fields generated by UXO clearance using high-order detonation and using low-order deflagration have been completed and reported on.

It was found that the deflagration method offers a substantial reduction in acoustic output over traditional high-order methods, with the peak being typically more than 20 dB lower.

A third phase has been initiated to further improve the information base, allowing further assessment of the clearance options. I understand that a potential 4th phase of the work involving offshore field work is also being actively explored in which comparative noise measurements would be made during actual UXO clearance campaigns using both deflagration and high-order detonations.

In the face of declining marine biodiversity it is critical that UK waters and the species that live there are properly protected.

Please be assured that I will follow any progress closely, and support efforts to hold the UK Government to account on efforts to manage and reduce underwater noise.

Yours sincerely,

Peter Dowd MP