Exposure to Nitrogen Oxides (NOx)

Key Learning

  • This was a routine lab procedure of catalyst calcining but the first time in new location. There were no written procedures for this process and was passed by word of mouth.
  • The lab set up was not secured and checked prior to start up.  


Researcher that detected odor was taken for medical evaluation and admitted to hospital overnight for observation.


An employee was performing the first catalyst calcining since the lab they worked in had been moved to a new location. The particular reaction carried out during the incident was a nickel nitrate decomposition. The lab is located on the High Bay Platform of room G16. This is an interior lab not exposed to the outside elements. The off-gas of the calcining process was bubbled into a beaker of water set on the bench top beside the reaction taking place. This bubbling process was used to capture the NOx that is released from the nickel nitrate decomposition so that it was not released to the immediate breathing zone of the employee. Typical protocol, provided to the employee via word of mouth prior to the experiment, calls for the beaker to be placed in a fume hood while the catalyst calcining takes place. However, on the day of the incident the beaker was on the lab bench during the experiment. While calcining the catalyst, the employee noticed a distinct metallic smell and realized he was being exposed to the NOx generated from the experiment. At this time he noticed the beaker used to scrub the off gas had been turned over on the lab bench, thus creating a direct release of NOx to the immediate environment.  The employee then verbally notified the other two employees working in the immediate area and they all evacuated simultaneously.

The employee immediately notified his supervisor of the exposure. The CAER safety representative was notified the next day. A call was then placed to the university health services and the employee was admitted for initial treatment and overnight observation.


  • No written procedures.

  • Lack of training and understanding of basic  safety precautions for the procedure.

  • Final check of set prior to initiating reaction.

Corrective Action

  • Develop written procedures for process.

  • Review requirements for exhausting all lab generated contaminated.

Date of Incident - January 11, 2011 at 2:00 p.m.