I'm hoping for advice from knowledgeble colleagues. I was burning magnesium in my newly-completed science lab. Just a few cm ribbon but it made enough white smoke to set off the fire alarm. The whole school was evacuated. I was under the impression that science labs should not have smoke alarms. Is that correct? Perhaps someone could point me towards the correct, authoritative, source of information. Also, is there a specific problem concerning smoke from magnesium? I have burned other substances, producing smoke, without triggering the alarm. Perhaps the particle size of magnesium oxide is such that it triggers smoke alarms more easily than other smoke.