What Are the Symptoms of a Propane Leak?
The first sign is usually the smell. Connecticut's Public Utilities Regulatory Authority says propane gas has no odor and that propane companies add a chemical called mercaptan to give it a distinctive rotten egg smell. NIOSH describes mercaptan as a sulfur-containing compound that smells like rotten egg or rotten cabbage, but says the odor may fade when gas leaking from underground lines passes through soil and concrete, and that materials such as drywall and plywood may also cause odor fade.
In the body, New Jersey's Department of Health says high concentrations of propane can decrease the amount of oxygen in the air and cause suffocation, with symptoms of headache, dizziness, lightheadedness, weakness, nausea, vomiting, loss of coordination and judgment, passing out and even death. The NIOSH Pocket Guide lists dizziness, confusion, excitation and asphyxia as symptoms of propane exposure, and frostbite from contact with the liquid.
If the odor is strong, the Connecticut regulator says to leave the premises immediately, tell others to leave, and then call your propane company from a neighbor's home. Burning propane indoors carries its own risk. For power outages, the CDC says never to use generators, grills or other propane-burning devices inside your home, garage or carport, because they produce carbon monoxide, an odorless, colorless gas that kills more than 500 Americans each year.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Government sourceConnecticut's Public Utilities Regulatory Authority says propane gas has no odor and propane companies add a chemical called mercaptan to give it a distinctive rotten egg smell. Connecticut Public Utilities Regulatory Authority ↗
- Government sourceConnecticut's utility regulator says that if a propane odor is strong, leave the premises immediately, tell others to leave, and then call your propane company from a neighbor's home. Connecticut Public Utilities Regulatory Authority ↗
- Government sourceNIOSH describes mercaptan as a sulfur-containing compound added to natural gas, n-butane and propane, with an odor described as rotten egg or rotten cabbage. NIOSH, CDC ↗
- Government sourceNIOSH says the odor of mercaptan may fade when leaking natural gas or propane from underground lines passes through soil and concrete, and that drywall and plywood may also cause odor fade. NIOSH, CDC ↗
- Government sourceNew Jersey's Department of Health says high concentrations of propane can decrease the oxygen in the air and cause suffocation, with headache, dizziness, lightheadedness, weakness, nausea, vomiting, passing out and even death. New Jersey Department of Health ↗
- Government sourceThe NIOSH Pocket Guide lists dizziness, confusion, excitation and asphyxia as symptoms of propane exposure, and frostbite from the liquid. NIOSH, CDC ↗
- Government sourceThe CDC says that during a power outage you should never use generators, grills or other propane-burning devices inside your home, garage or carport, because they produce carbon monoxide. CDC ↗
Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.