Use your combustible gas indicator (CGI) to monitor the air around the building.

If gas concentrations are well below the lower explosive limit of 5% and you can enter the building without risk, check for natural gas in the following locations:

• The areas where any underground water, sewer, electric or drain lines enter the building
• The regulator, meter bar and all piping that supplies natural gas as well as the piping around all gas-fired appliances, such as water heaters and clothes dryers
• The spot where the gas service enters the building
• Any cracks in the wall
• All high points in the ceiling where natural gas could collect