The key facts

  • 15 guests of the Ling Bao hotel were poisoned by chlorine, four were hospitalized
  • The chlorine excess alert system worked via Outlook, which failed to deliver the emails due to an outage
  • The pool was temporarily closed to replace the water and then reopened

Poisoning at the Ling Bao hotel

On Friday, 15 guests of the Ling Bao hotel at the Phantasialand amusement park in Brühl near Cologne suffered chlorine poisoning after swimming in the pool. The cause was a malfunction in Microsoft services, the newspaper Bild reported.

How an email outage led to excess chlorine

The hotel pool is equipped with an automatic chlorine dosing system that alerts staff when chlorine levels exceed the norm — but it does so by email. Due to a malfunction in the Outlook email service, the warnings did not reach the park on Friday, and too much chlorine got into the water.

Consequences for the guests

After swimming, guests complained of airway irritation and nausea. Four were taken to hospital: one in moderate condition and three with mild symptoms. The others were examined by an emergency doctor and did not need to be hospitalized.

What happened after the incident

The pool was temporarily closed to replace the water, but was later reopened to visitors. The incident exposed the vulnerability of a safety system tied to a single email service: the alert about a critical deviation had no backup channel, and it was this, according to Bild, that allowed the excess to go unnoticed.