Levels of legionella have been found on Thameslink train toilets and the Rail, Maritime and Transport union (RMT) has called for an urgent meeting as workers are threatening to strike.
Thameslink has been accused by the RMT of a “pitifully inadequate” approach and the rail operator has been accused of gambling with passengers and workers health.
Legionnaires disease is a severe form of pneumonia and can cause a less severe, but serious illness called Pontiac fever.
Thameslink services operate in London, Cambridge, Brighton and many other cities across the UK.
The rail operator said that they have only found “very low” levels of the disease and it is “extremely unlikely” there will be any harm to passenger or workers.
Thameslink’s train services director Rob Mullen said, “A very low level of legionella was found to be present during testing in a small number of our Thameslink Class 700 train toilets.
“While it is extremely unlikely this would cause any harm to passengers or colleagues, the toilets affected were immediately locked out of use.
“The trains were taken out of service and these toilets have now been drained, bleached and had their tanks completely re-filled.
“There is no recorded case of anyone, ever, having contracted legionella from a train.”
However, the general secretary Mick Lynch has called for an urgent meeting of Thameslink’s joint safety committee.
Lynch said, “RMT has been raising concerns for weeks now, and the latest cavalier approach from the company is pitifully inadequate and is an outright gamble with passenger and staff health.
“We have now declared a dispute and, be in no doubt, if we don’t get serious action we will ballot our members and do whatever is required to end this reckless approach to a potentially lethal situation on these increasingly busy trains.”
Thameslink is a part of the Govia Thameslink Railway said in a statement, “Legionella can potentially be spread through atomised water droplets in the air in enclosed spaces, but water in our toilets is gravity-fed, which makes this extremely unlikely and further lowers the already very low risk. However, as a precaution, we immediately closed the affected toilets and took these trains out of service.
“The toilets affected have been completely drained, bleached and re-filled to rectify this situation.
“All other parts of the trains were unaffected, including our air con systems, which do not use water (they use refrigeration to cool the air).
“Therefore, as Legionella spreads via water-based vapour, it is not possible for it to be present in our air con systems.”