The 1424MWe PWR was taken off line on 8 October and Environment Minister Jürgen Trittin has said it will remain down until the safety violations are "fully explained". Operators had discovered that three out of four safety injection system tanks of borated water had insufficient boron concentrations but did not report it to regulators; soon after, it emerged that the operators had brought the unit online after a recent outage without reporting that the coolant level in emergency cooling tanks had been found to be several metres too low. State regulators said the event corresponded to INES (International Nuclear Event Scale) level 2.
As a result of the incident, Gerhard Goll, CEO at EnBW, has forced the departure of Ulrich Gräber, the Executive Vice President responsible for technical matters, and his counterpart at the EnBW parent company, Klaus Jasper. Goll has also forced the resignations of the top labour representative at the reactor as well as the manager of the unit.
Soon after the incident, Goll ordered an inquiry into the reliability of emergency cooling systems at all its nuclear plants. The findings gave details of additional, but relatively insignificant, events at two other plants in recent years, involving deviations from technical safety requirements for emergency cooling systems. These events, at the Obrigheim and Neckarwestheim 1 nuclear units, have now been declared to the regulatory authorities. EnBW said they were "fundamentally different" to the incident at Philippsburg 2.