A ship using the River Tees was detained by the Maritime and Coastguard Agency after the discovery of potentially deadly legionella on board.

Recent papers from the River Tees Port Authority recorded details of the incident in October, describing how the vessel had previously failed for legionella contamination in its water system.

A report for members of the authority said: “The levels detected were deemed to be grossly contaminated and therefore posed a risk to both the crew and contractors on board.”

It said relevant stakeholders were consulted about the best course of action to protect people on board, including the port medical officer, the Maritime and Coastguard Agency (MCA), the harbour master and the ship’s agent.

Darlington and Stockton Times: PD Ports' Teesport. Photograph: Stuart Boulton..

The report said: “The MCA determined the vessel was unfit to sail and detained it pending specialised cleaning and disinfection of the tanks and water system. 

“Following further cleaning and disinfection by an independent company and further samples, results were favourable with no legionella found in the samples taken. 

“The vessel was released from detention and allowed to sail nine days after it was first detained.”

Legionella – a type of bacteria – is a cause of legionnaire’s disease, a serious lung infection which is typically contracted from breathing in tiny droplets of water containing the bacteria and can be fatal if left untreated.

It can be found in the likes of air conditioning systems, humidifiers and spa pools and hot tubs.

Ships using the Tees require sanitation certificates and can be inspected on request, having to supply a declaration of health before officials board.

Twenty five inspections took place between August and October last year in Hartlepool, Middlesbrough, Redcar and Cleveland and Stockton.

Requests for water samples can also be made, which are then sent off to a laboratory to be analysed.

The report explained: “Any unsatisfactory samples are provided with advice and information and a recommendation to re-sample at their next port of call.”

Fifty four samples were taken over the period with 46 deemed satisfactory and eight unsatisfactory.

The River Tees Port Authority, which has been administratively based in Guisborough for many years, has a number of functions including monitoring hygiene and environmental standards on vessels entering Teesport and ensuring they comply with international hygiene and pollution laws.

It also aims to ensure that food, feed and other relevant products entering the UK through Teesport, which has the status of a border control post, have been legally imported and comply with relevant controls.

The present authority was established in 1982 and is funded each year by the four ‘riparian’ authorities of Redcar and Cleveland, Stockton, Middlesbrough and Hartlepool Council, who between them contributed £141,700 this financial year.