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.

Peroxide Explosion Injures Campus Researcher

November 30, 2006
Office of Environment, Health, and Safety
What Happened?

An undergraduate student researcher was working at the laboratory bench when the apparatus she was using exploded, sending glass fragments into her face and upper torso. The researcher was using a rotary evaporator (rotovap) to remove organic solvents from an azobenzene precipitate. She adjusted the bottom flask which then exploded sending glass towards her face, hitting her safety goggles and forehead. Lab personnel helped her to the safety shower and called 911. She was taken by ambulance to the hospital where she received stitches above her eyes and other treatment...

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.

illustration of a biohazard symbolHow Do I: collapse all...

Overpressurization 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 waste overpressurization 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 overpressurization. The hood...

Workplace Safety

California state regulations require every employer to establish, implement and maintain an effective Injury & Illness Prevention Program (IIPP). In August 2017, the University adopted a campuswide Workplace Safety Program that serves as the University’s central IIPP for creating a safe and healthful work environment. Having one program for the whole University helps to improve access, consistency, and usability across all departments. EH&S is the responsible department for overseeing the campuswide Workplace Safety Program. The campus Workplace Safety Program is based on the Injury...

Lessons Learned: β-Mercaptoethanol (BME) Spill

June 30, 2026
What Happened

β-mercaptoethanol (BME) is a hazardous substance characterized by its acute toxicity, corrosivity, and reproductive risks. Additionally, its thiol group gives the compound a distinct, pungent odor.

A researcher was handling a bottle of BME when it fell and spilled approximately half its contents. This resulted in the researcher’s pants being saturated with the chemical, as they were not wearing a lab coat. The spill also impacted the surrounding floor and laboratory surfaces, resulting in the strong odor, similar to...

Employee Receives Electrical Shock

March 31, 2004
Office of Environment, Health, and Safety
What Happened?

A university employee was changing ballasts above a drop ceiling in a department reception area. The employee received an electrical shock from a 277volt circuit and was knocked off a step stool that she had placed on top of the reception desk. She fell from a height of 46.5 inches, but received only minor injuries and returned to work the following day.

What was the cause? The power source was not locked and tagged out. Instead, the light switch was turned off. The ladder to be used was too large to work from behind the reception desk, so a...

Injury Caused by High Voltage Capacitor Discharge

May 31, 2005
Office of Environment, Health, and Safety
What Happened?

A campus employee working in an electronics shop was repairing a power supply unit. The cooling fan had not been working properly, causing the unit to overheat. The employee replaced the defective cooling fan and then reached into the open top of the power supply unit to check the airflow from the replacement fan. The employee either made contact with a charged capacitor or was close enough (within 1/4") to allow electricity to arc to his hand causing an electric shock that entered his left hand and exited through his right hand.

Immediately after the...

Lab Fire Caused By Hotplate Heating Oil Bath That Injured Researcher

March 31, 2013
Office of Environment, Health, and Safety
What Happened?

A chemistry researcher was using an older model hot plate to heat an oil bath to 120-150°F. He borrowed the hotplate from someone else and was not familiar with the temperature controls. On this particular hot plate the temperature dial could go around from “LO” to “OFF” and back to “HI” heat. The researcher thought he had turned the hotplate “OFF” but it was still in the “ON” position and 30 minutes later the mineral oil bath ignited.

Fortunately, the oil bath was in a fume hood which kept the flames and fire inside the hood, it was reasonably clean and no other...

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.