KEY POINT
Know the 6-step process for making decisions about evacuation and SIP in the event of a chemical release.
Step 1: Determine the characteristics and identity of the released chemical.
- The physical state of a chemical, its density in relation to air, and its vapor density influence how fast the chemical will be released and the concentration once it escapes from its container. This is important because it influences whether people will have enough time to evacuate.
- Generally, gaseous hazardous materials are more dangerous than liquids or solids. Materials that have a vapor density of greater than 1 are heavier than air and will tend to hug the ground and will not dissipate as readily. Chemicals that have a high vapor pressure tend to volatilize quickly and produce a more concentrated plume than materials with a relatively low vapor pressure.