Incident description

Lab members were cleaning out materials left behind from a previous graduate student. Materials were in secondary containers labeled acid and believed to be sulfuric acid dilutions. The lab members added sodium bicarbonate to the secondary containers until no more gas was evolved, then dumped the mixture into the sink. After doing this for a couple of containers, a rotten egg smell permeated the lab. The students evacuated immediately and contacted their DSC. The DSC called 9-1-1 and EH&S (530-752-1493) for assistance. 

What went right?

The students responded correctly by evacuating and asking their DSC for assistance. 

What should have been done differently?

Lab cleanouts should be coordinated with hazardous waste – not just for cleaning out an entire lab, but also for when a student leaves materials behind. Labels on secondary containers that have been abandoned can’t always be trusted and it is safer to dispose as hazardous waste. 

Nothing should be disposed down the sink except water. If there’s any question, send the material out as aqueous waste through EH&S. Permission to dump something down the sink must be obtained from local-limits. 

Neutralization steps can occur as part of an experimental process but cannot be used to treat waste. 

How to prevent this in the future:

Proper labels including name and primary hazards must be included on all secondary containers. Laboratories should implement proper cleanout procedures for soon to be leaving students/researchers.