An environmental analyst is preparing a calibration standard of concentrated nitric acid (HNO3\text{HNO}_3HNO3) to analyze heavy metal contamination in a soil sample. Nitric acid is a strong, highly corrosive oxidizing agent that can release toxic nitrogen dioxide gas (NO2\text{NO}_2NO2) upon decomposition or reaction.
State one specific safety precaution, other than wearing a lab coat, that the analyst must take when preparing this calibration standard.