WebWISER is a website sponsored by the National Institute of Health. The website helps the user identify unknown chemical agents through physical characteristics and observable sensing (visual, smell, density, feel, even taste - but that's not recommended unless inadvertent ingestion occurs)
http://wiser.nlm.nih.gov/ Wireless Information System for Emergency Responders.
As you discover an unusual odor or sheen, you evacuate the work area and enter WISER. You navigate to the identification area and fill in a simple form detailing what you observe. Is the product floating or sinking in water? Color? Odor? Taste? From these data, WISER offers some identifications of the potential contaminant and a how-to deal with the situation.
The site can be used as a library of Manufacturers Safety Data Sheets (MSDS) information. Be familiar with chemicals and products you use. Print instructions for preventive handling and spill cleaning. Use these chemical data in field safety meetings.
Mixing chemicals creates new dangers. Read those MSDS sheets for warnings about what chemicals to avoid mixing with ones you use. For example, bleach and ammonia should not be mixed. Store these lethal combinations separately.
Do your employees know how to handle a diesel fuel spill? How about proper response to puncturing a buried heating oil tank? Gasoline tank?
Courses teach upper (UEL) and lower (LEL) explosion limits. Too rich (UEL) and too lean (LEL) fuel and air mixes will not ignite. Please caution your employees: if a tank environment is above the UEL, it is at risk to be vented into the explosive zone as air enters the area and fumes escape.
This website offers a quick reference to chemical identification. When accepting a contract for demolition or excavation, it is wise to bookmark known potential contaminants for quicker reference.
Be safe. Know your chemical or petroleum product. Let professionals remediate any release on the jobsite. Take time to familiarize yourself with the navigation on this site.