Lessons Learned

Reports on incidents that involve injury, exposure (real or potential), or significant damage property. Lessons Learned detail what happened and how similar incidents can be avoided in the future.

Biological Safety

Providing support, in the form of risk assessment, review, consultation and training, for research at UC Berkeley that involves the use of recombinant DNA, biohazardous materials and biological toxins.

Biosafety How Do I: collapse all expand all...

Lesson Learned: Methyllithium Fire - Quenching of Pyrophoric Materials

April 24, 2026
Solid methyllithium remnants were wiped up in a glove box using kim wipes, which were then wrapped in aluminum foil. This foil packet was then transferred to a fume hood for the quenching procedure. Isopropanol was added dropwise to this foil packet. Upon addition, the kim wipes and isopropanol started to smolder and caught fire within the fume hood. The researcher quickly put the fire out with a fire extinguisher and reported the incident to EH&S.

Lesson Learned: Sodium Metal Fire - Quenching of Water Reactive Materials

April 24, 2026
Small amounts of residual sodium metal (Na) on lab spatulas and tools were quenched by placing the items in an isopropanol bath within a fume hood. Not all tools were fully submerged in the solvent bath, and the reaction was not stirred. Water was then added to the isopropanol bath. Unreacted sodium remained on the tools and reacted upon contact with the water, igniting a fire. The heat from the fire damaged the fume hood sash and caused melting of nearby containers.

Nitric Acid Waste Over-pressurization Event

July 3, 2018
Office of Environment, Health, and Safety
What happened?

A graduate student researcher was consolidating aqueous nitric acid solutions into a 4-L bottle marked as hazardous waste. The bottle was stored inside a fume hood along with other waste bottles, organic reagent bottles, a hotplate and an oil bath. The fume hood sash was left open when all researchers left at the end of the day.

Several hours later, a custodian entered the lab and saw broken glass and brown liquid on the floor. It appears that the nitric acid waste was stored in a bottle that contained residual organic compounds, the combination of which generated...

Discovery of an Old Container of Potentially Explosive Chemical

June 30, 2008
Office of Environment, Health, and Safety
What Happened?

While working in a UC Berkeley laboratory, a graduate student discovered the presence of an old experimental set-up, which was labeled as containing a small amount of hydrazoic acid, in a shared cold room with no responsible contact person. This material is a potentially explosive chemical under certain circumstances, so the student referred the set-up to the Department Safety Coordinator (DSC). The DSC requested the assistance of EH&S who recommended that the set-up be disposed of by an explosives material contractor because very little was known about the source...

Explosion of Concentrated Hydrofluoric Acid Waste Solution

June 30, 2008
Office of Environment, Health, and Safety
What Happened?

A graduate student in a UC Berkeley laboratory discovered the aftermath of a chemical explosion upon arrival at the laboratory he shares with other graduate students. The extensive contamination was caused by the explosive rupture of a plastic bottle of liquid waste kept inside the hood. According to the container label, one of the components inside the ruptured bottle was hydrofluoric acid. The investigation revealed that an incompatible material may have been poured into the same container causing the reaction and resulting explosion. The hood, floor and walls near...

Exposure to Bromine During a Laboratory Refrigerator Clean-up

June 30, 2008
Office of Environment, Health, and Safety
What Happened?

While performing a chemical inventory inside a laboratory refrigerator, a UC Berkeley graduate student observed the presence of condensate on the inside walls of the refrigerator. This student and two other graduate students proceeded to clean the refrigerator walls, assuming that the condensate was water. When one of the students noticed a bottle of 99% bromine had a small leak, clean-up was immediately stopped, a sign was posted on the door to keep away, and the Department Safety Coordinator (DSC) was notified of the accident. The DSC summoned EH&S clean-up...

Exposure to Poisonous Chemicals Due to Improper Storage and Unsafe Work Practices

June 30, 2008
Office of Environment, Health, and Safety
What happened?

A graduate student working in a UC Berkeley laboratory needed a chemical from an overhead shelf. To reach the chemical, the student stood on tiptoe and leaned on the edge of a shelf. This pressure caused the shelf to shift and chemicals to fall. Among the bottles that fell were two that were covered with aluminum foil instead of the original screw-on caps. Those containers held strychnine powder and azure blue dye. The contents fell on the researcher, bench, and floor. The exposed researcher spent 15 minutes under a safety shower and then went to the Tang Center for...

Acetone Fire

July 31, 2008
What happened?

A student worker in a Berkeley campus laboratory was refilling squirt bottles with acetone from a larger dispensing container when he spilled approximately one cup of acetone liquid onto the floor. Due to lack of training, and/or an error in judgment, the student lit the acetone with a match to burn it off instead of following proper spill clean-up procedures. While doing so, the student accidentally knocked over another uncapped squirt bottle on the benchtop that was filled with acetone. This additional acetone ignited and set-off the fire sprinklers in the room,...

Accidental Mixing of Bleach and Acid

October 31, 2009
Office of Environment, Health, and Safety
What Happened?

A researcher working in a laboratory glassware washing area thought she should refresh the bleach solution for soaking lab glassware. In an "inattentive moment" she added fresh bleach to what she thought was the bleach soaking tub; unfortunately the tub did not contain bleach but contained 5% hydrochloric acid. The acid solution (with bleach) immediately turned from clear to yellow. She quickly realized that bleach and acid should never be mixed because toxic chlorine gas can be created. She immediately had everyone leave the room; she considered calling 911, but since...