<http://schema.org/description>
"Americans have been using natural gas for decades. It fuels homes and factories, powers our appliances and goes into making products like antifreeze, medicine and explosives. Since 1949, its use and domestic production have risen each year."^^<http://www.w3.org/2001/XMLSchema#string>
<http://science.howstuffworks.com/environmental/energy/safe-natural-gas.htm>