Hydrogen peroxide, strong oxidizing acids such as nitric, perchloric and sulfuric acids and mixtures such as Piranha or Aqua Regia are used as etches to remove organic residues from silicon wafers and other materials. These chemicals are dangerous because of their strong corrosivity and the propensity of waste solutions to evolve gas due to oxidation of organics or decomposition. EHRS has responded to several incidents of container ruptures in the School of Engineering and Applied Sciences involving these waste materials. In a recent incident the waste bottle ruptured sending shards of glass and plastic through the lab.



Special care must be taken if you generate waste containing these chemicals. Please observe the following safety precautions:

• Collect waste containing oxidizing acids or peroxides in plastic containers sealed with special gas venting caps. Do not use glass containers. Plastic waste containers with gas venting caps are available from EHRS.  Do not fill the container more than half way.

The waste bottle must be stored in a special secondary containment bucket that will shield lab occupants from corrosive spray if the container ruptures. Do not store waste in the lab for long periods of time.

• Make certain the waste is placed in a secondary containment and has a waste label attached to the container. Keep the fume sash closed when not working in the hood.

• Inform EHRS that your waste may off-gas when you request a waste pickup.