Hexamethyldisilazane Spill

Incident Description

EH&S' daily on-call safety specialist received a report that a bottle of hexamethyldisilazane had been dropped and that approximately 500 mL of liquid was on the floor of the lab (not inside a chemical fume hood). The Safety Data Sheet (SDS) lists the hazardous properties of this chemical as highly flammable, toxic in contact with skin, and harmful if inhaled.

When the on-call professional from EH&S arrived on scene, the researchers had evacuated the lab and were waiting in the hallway along with the UCD Fire Department Haz-Mat Team. After confirming it was safe to enter the lab, the EH&S on-call safety specialist located the labs spill kit and used the absorbent material in the kit to stop the liquid from spreading. The spill was then cleaned with the assistance of the hazardous waste specialists at EH&S in accordance with the accidental release measures outlined in the SDS. All absorbent present in the kit was used, and more was needed to absorb spill; the EH&S hazardous waste specialist supplied additional absorbent. The absorbent material and broken glass was swept up and disposed of as hazardous waste. The researchers then vacated the lab for 24 hours to allow any vapor to dissipate.

What Went Right?

• The lab called 911 and the EH&S on-call safety specialist
• The lab had a stocked spill kit on hand and consulted SafetyNet 13 before acting
• The lab air pressure was negative relative to the hallway so that no odor or vapor spread into the building
• The lab recognized that despite the relatively low hazard level and small size of the spill, they did not feel comfortable cleaning it up on their own.
• The lab had the SDS on hand to share with the first responders and EH&S

What Should Have Been Done Differently?

Although the spill kit was fully stocked, this spill consumed all of the absorbent. An additional bag of absorbent would have been useful in this case.

How to Prevent This in the Future

• The lab could go over the SDS of their commonly used chemicals in future lab meetings, and during standard operating procedure training
• Initial and regular refresher spill training, optimally coupled with hands-on mock spill training scenarios, can empower lab personnel to clean up small spills
• Be sure to restock all used components of spill kit when spill occurs