Unattended Experiment Causes Exposure to Nitric Acid

What Happened?

A lab member was exposed to nitric acid when a researcher from a neighboring lab performed a digestion using the lab's thermomixer and left the experiment unattended. The thermomixer was not inside a chemical fume hood and the researcher had left the tubes uncapped. While the researcher was gone the thermomixer exceeded the target temperature for the experiment and boiled of nitric acid. The lab member entered the lab and began to feel a burning sensation to the face, eyes, nostrils and throat after about 5-10 min. He investigated the source of the problem and discovered the uncapped tubes in the 95°C thermomixer. He placed the thermomixer into the chemical fume hood and reported the incident to his PI. The lab member subsequently located the researcher responsible for the experiment. When it became clear that the lab member had been exposed to nitric acid, he rinsed his face with water and contacted EH&S. He was advised to call 911 and subsequently received medical attention by the arriving paramedics. A sign was placed outside the lab indicating a chemical spill in that lab.

What Was The Cause?

Nitric acid was boiled off outside a chemical fume hood.

What Corrective Actions Were Taken?

• Provide training for procedures containing hazardous chemicals
• Provide specific training for use of laboratory equipment
• Generate an SOP for digestion procedures involving nitric acid
• Review emergency procedures including the locations of eyewash stations and emergency showers in the lab

How Can Incidents Like This Be Prevented?

• Perform experiments that involve hazardous, volatile chemicals inside a chemical fume hood
• Never leave experiments containing hazards unattended
• Always control conditions for experiments containing hazards


> SDS for Nitric acid
> Featured Chemicals: Nitric acid


If you become aware of a burning sensation or smell:

• Alert co-workers

• Leave the lab and close doors

• Inform your supervisor

• Call EH&S

• Investigate only if you feel safe enough to do so


Nitric Acid

• Very hazardous to skin (corrosive, irritant, permeates, causes burns) eyes (corrosive), ingestion

• Explosive in the presence of reducing and organic materials, metals or alkali