Final report says construction activities near the effluent drainage system caused contamination

Construction workers were responsible for the spread of foot and mouth disease in the Surrey outbreak, the HSE has confirmed.

In its final report about the foot and mouth outbreak at the Pirbright site on 3 August, HSE chief executive Geoffrey Podger said construction vehicles had “relatively unrestricted access” to the site near the contaminated drainage system.

He said: “In our opinion, these construction activities – very near to the effluent drainage system – are likely to have caused disturbance and movement of soil in a way that contaminated some of the vehicles with the live virus.

“We established that some of the vehicles, probably contaminated, drove from the site along a road that passes the first infected farm. We conclude therefore that this combination of events is the likely link between the release of the live virus from Pirbright and the first outbreak of FMD.

"We have drawn our concerns about the breaches of biosecurity, together with a number of recommendations, to the attention of the Pirbright site regulator – Defra – so that they can be rectified."

The investigation found it was possible for the live virus strain O1BFS to enter the site effluent drainage system. Waste water then leaked out on to surrounding soil.

It found evidence of long term damage and leakage, including cracked pipes tree roots breaching pipework, and unsealed manholes.

The HSE also believes excessive rainfall in July may have increased the potential for virus release from the drain.