Handling Gas Line Leaks
Natural gas line leaks are extremely dangerous. Natural gas – Methane – becomes explosive when it mixes with air. This is the kind of accident that kills. Natural gas explosions and fires can easily destroy homes and structures. Afterwards, ruptured gas lines continue to flare and burn until the supply of gas is turned off. For these reasons, natural gas line leaks must be repaired immediately.
Safety Facts about Natural Gas
Methane becomes explosive when it mixes with the oxygen that is present in air. This gas-air mix becomes explosive only when the gas proportion is between 7 and 15%. If less than 7%, it could still suffocate you. The suffocation hazard begins at about 5000 parts per million (ppm) – or 0.05% – well below the explosion limit. You can suffocate from a gas leak long before enough methane is present to burn or explode.
Below 5000 ppm, methane can still cause disorientation, dizziness, headaches, and nausea. Any prolonged exposure above 1000 ppm is considered dangerous and will slowly poison your body, damaging internal organs.
Natural gas itself is a colorless, odorless gas. It is lighter than air. So if there is a leak in the basement (or on lower floors), methane gas can still rise up and flow into your living or work area.
Natural gas companies add sulfur-containing compounds called Mercaptans (methanethiol) along with other sulfides. Strong and pungent, Mercaptan has a uniquely sharp and distinctive odor similar to garlic. Mercaptan can be detected by your nose when it is present in concentrations as small as 10 parts per billion.
Many other sulfur-containing molecules are also added make escaped natural gas even easier to smell. All of these compounds have sharp unusual odors including the classic “rotten egg” smell.