DEADLY legionella bacteria were discovered at the depot for the Edinburgh trams – just three months after an outbreak that killed three men.
In June last year Legionnaires disease – caused by legionella – swept through the Capital after industrial cooling towers were thought to have spewed contaminated water droplets into the atmosphere
More than 100 people were hospitalised after they breathed in the vapour and three men died.
But it has now emerged the same bacteria was found in a tram carriage cleaning unit at the end of September last year.
Council bosses insist there was only a “trace” of bacteria and cleaned equipment “over and above legal requirements” and no one was at risk.
But critics fear it could lead to another outbreak as the discovery shows hygiene standards are slipping as a result of “corporate negligence”.
Legionnaires disease is caused by legionella bacteria multiplying in warm stagnant water such as car washes, hose reels and man-made equipment that stores water.
The findings emerged yesterday (Monday) after an inside source revealed tests were carried out on September 27 last year.
The checks found 20 colony-forming units per litre (CFU’s) in the washing system at the trams depot in the Gogar area of the city – just three miles from the original outbreak in Saughton.
If there are less than 100 CFUs per litre then there is said to be no cause for alarm.
If there are between 100 and 1,000 CFUs per litre then contaminated equipment must be sterilised.
But anything over 1,000 CFU’s per litre can lead to outbreaks similar to the one that scourged the city last year.
Jay Paisley, a 49-year-old who spent three weeks in a coma as a result of last year’s outbreak, said: “There’s meant to be people monitoring the environment for this.
“We are entitled to not be poisoned by corporate negligence.
“It’s down to people not cleaning stagnant water properly and it’s very concerning that this happened in Gogar because there is RoseburnPrimary School nearby.”
Expert Allen Wilson said conditions similar to the tram cleaning system could cause an outbreak of Legionnaires disease.
He said: “You need a few things for legionella to occur: water that’s been allowed to stagnate and needs to be at a temperature of between 20 and 40 degrees C.
“The closer it is to body temperature, the more it grows. It also needs some way to be converted into an aerosol droplet like you would get from shower heads.
“Something like a common pressure cleaner, like you might find at a washing unit, could create these respirable droplets.”
Edinburgh City Council said they are satisfied there is no danger to tram workers and members of the public but the site will continue to be checked every month.
A spokesman said: “In terms of how these bacteria are monitored there was only a trace of legionella bacteria detected in a washing unit in September.
“No staff or members of the public were at risk at any point.
“The area was treated and sterilised by independent water hygiene specialists immediately in a way that went over and above legal requirements.
“The building continues to be monitored monthly and wash systems are flushed daily to maintain the highest safety standards.”