Surface fires can be deadly and many things at a production site are flammable. It is imperative that all fire risks are maximally mitigated, while the site and crew must be prepared to act quickly and safely in the event of a fire. It’s estimated that about 16% of oil and gas industry fatalities are caused by fires, explosions, or electrical accidents.
The lower explosive limit (LEL) for methane is 5% and the upper explosive limit (UEL) is 15%. If the concentration of methane falls between the LEL and UEL in the presence of oxygen and an ignition source, a fire will ensue. However, methane is not usually the only gas present at a well site. Others might include ethane, propane and/or butane. The LEL and UEL of these other hydrocarbons tends to be much lower than methane, so one must never grow complacent.
This should go without saying, but it is never okay to smoke at a well site, no matter what phase the project is in. Smoking serves as that afore-mentioned ignition source and can ignite invisible, highly explosive vapors emanating from the well or production equipment.
Static electricity is another major ignition source. Everyday actions such as answering a cell phone can ignite vapors.
As you can see, it is best to always be vigilant against fire potential on and near a well site or production facility.