Lab Incident – October 4, 2011 Hydrogen Peroxide

What Happened? ….Can you guess what may have happened?.... Researcher prepared a one liter bottle of 4% NH4OH (ammonium hydroxide) + 4% H2O2 (hydrogen peroxide) in water at ~70-80°C (158°F-176°F) three months prior to incident Used for removal of organic contamination on substrate of silicon wafers Solution stored in a clear glass bottle on bench shelf ….Can you guess what may have happened?....

Photos show glass shards on shelf, bench top, and floor Bottle bursts in the lab !!! (Thankfully at night when no one was in lab space) Photos show glass shards on shelf, bench top, and floor We founds shatters of glasses all over near my bench. This is my bench and the arrows show how far the shatters have reached. We initially suspected that this was due to the overheated polymer solution during sonication.

WHY ? Some properties of Hydrogen Peroxide Strong oxidizer Corrosive Incompatible with organics and reducing agents Light sensitive 2H2O2 -> 2H2O + O2 (exothermic decomposition) If 1 Liter of H2O2 decomposes, 20 Liters of O2 is produced (20x) High Pressure The decomposition rate depends on influencing factors such as temperature, pH, presence of impurities and catalysts, etc. But later that day I found the label of the exploded bottle with my name on it. The solution was found to be a dilute hydrogen peroxide solution for cleaning silicone substrate. I used it only once 3months ago, so I forgot of its existence. To prevent further accident like this, we must know the properties of H2O2.

Storing Hydrogen Peroxide Solutions Store original containers from supplier per MSDS Dilutions – Do not contaminate during preparation Store in brown glass or plastic container that light will not penetrate and at cool temperature Use a vented cap to reduce pressure build up as necessary (e.g., if mixed with a catalyst or at high concentrations) or dispose of solution in timely manner This is how to properly store h2o2 solutions and wastes.

Storing Hydrogen Peroxide Wastes Waste solutions Use vented cap to reduce possible pressure buildup since more contamination of waste solution is likely. Vented caps to fit 4L bottles are available at EHS Office via environment@mit.edu . Remove solutions and wastes when done with experiments. Contact EHS immediately for removal at x2-3477 if concern of bottle being over pressurized.

Reporting “Near Miss” Incidents Researcher immediately reported 10/4 incident to PI (note: would have been helpful to also report this to EHS Coordinator) EHS Office and Coordinator find out about incident on 10/24 when EHS called for pick-up of waste bottle PI asked researcher and EHS to present at lab group meeting on 10/25 EHS Coordinator shares lessons learned from this incident at meetings with DLC EHS Reps on 11/30 and fellow EHS Coordinators on 12/13