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 rotten eggs or natural gas, lingering in the lab.
The lab performed initial spill clean-up activities before contacting EH&S. When the odor remained noticeable, EH&S was notified and responded to assess the situation and support the remaining clean-up efforts. The affected surfaces were cleaned with a bleach solution to oxidize the thiol groups and neutralize the odor. To ensure safe air quality and clear remaining vapors, fans were set up to help increase laboratory air exchange rate.
What went right?
-
EH&S was notified promptly to help clean up the spill.
-
The lab was evacuated and signs posted on the doors to not enter.
-
EH&S was notified the following day that there was a lingering odor. EH&S conducted a more thorough cleaning with bleach.
What should be done differently?
-
BME must be handled in a fume hood due to its hazards and low odor threshold.
-
Minimum PPE (lab coat, gloves, safety glasses) should be worn while handling hazardous materials.
-
Secondary containment should be used for transport and storage to help with containment in case of a spill.
-
The chemically contaminated clothing should be immediately removed and the affected skin flushed with water for 15 minutes. The affected individual should then seek medical attention at the Tang Center or Alta Bates Medical Center.
Additional information
The incident was caused by working with BME on a benchtop without the use of secondary containment. A majority of the BME landed directly on the researcher’s pants. A lab coat serves as an important layer of protection for the researcher by helping limit direct chemical contact and reducing the potential severity of an exposure. Furthermore, because the work was being performed on the open bench rather than inside a fume hood, the potent vapors were able to disperse throughout the laboratory.
What corrective actions will be taken?
-
The lab group will discuss the importance of proper PPE (at minimum a lab coat, gloves, and safety glasses) during group meeting.
-
The SOP for handling β-mercaptoethanol will be revised to ensure all work occurs in a fume hood and that a bleach solution will be used to neutralize the thiol and associated odors.
-
The lab will obtain and use secondary containment for the storage and transport of BME.
Lessons Learned
- This incident emphasizes the importance of wearing proper PPE while handling hazardous materials, as well as using proper engineering controls, such as a fume hood.
- While working with BME, or other thiols, it is important to have a bleach bath set up to oxidize items (pipette tips, glassware, etc.) in contact with the thiol to remove the potent odor. The bleach bath should be prepared as an approximately 50:50 solution of commercial bleach and water, or a total concentration of 5-6% sodium hypochlorite.
- It is also important to confirm bleach compatibility before use, and bleach should not be used if amines, ammonia-containing compounds, or other incompatible chemicals are present in the solution.
- Moving forward, the laboratory will wear the minimum PPE, use a fume hood for hazardous materials, and review the SOP before conducting work.