gazette@watserv1.waterloo.edu (Chris Redmond) (12/20/90)
According to the UW safety office, the odour around the science buildings which led to some evacuations yesterday was the result of improper disposal of chemicals -- specifically, an estimated 100-200 ml (less than a cup) of mercaptan, which among other uses is the liquid usually added to natural gas to give it a smell. Mercaptan itself is not particularly toxic, and not explosive. Someone apparently dumped this substance down a drain in the Earth Sciences and Chemistry building, rather than putting it in a bottle and delivering it to the free waste-chemical disposal service in Chemistry 2. Fume hoods picked up the mercaptan and dispersed it through ESC and (with the help of yesterday's north wind) surrounding buildings. ESC and Biology 1 were officially evacuated, and many people left other buildings nearby and as far downwind as Engineering 1. When the experts traced the problem, they flushed out the offending sewer with detergent and large quantities of water. This morning only a slight odour lingers. No injuries are reported.