Carbon monoxide alarms turned off before Evergreen State student death

If you read the article, they had just installed a new water heater and did the ventilation wrong. There were also a few instances through the course of the day where the detectors were triggered and handled. There was a lot of negligence from the vendor that installed the ventilation and especially the maintenance that did not consider the recent work that had been done and assumed that all the detectors were suddenly faulty at the same time.