Originally Posted by
xcitation
Slow pinhole leaks can be as dangerous as a rapid decompression. The resulting insidious onset of hypoxia on the brain can be similar to alcohol intoxication. The effects vary by individual: impaired cognitive function, euphoria and overconfidence, lethargy or angry and un-cooperative. There are sensors and alarms to warn of loss in cabin pressure which should result in immediate action.
Helios Airways Flight 522 is a tragic example.
A slow pinhole leak is only dangerous if the crew allows themselves to become distracted to the point they ignore the aircraft's automated warnings.
When the cabin altitude reaches 10,000 feet an alarm will notify the crew. At roughly 13,000 feet the passenger oxygen masks will drop.