No, it is not normal for a gas fireplace to give off a strong smell for this long of a time. The strong “urine” smell could be urethane insulation that is too close to the firebox or vent pipe. Or if you are running on natural gas, it could be the mercaptan odorant in the gas which is leaking.Click to see full answer. In this way, why do I smell gas from my gas fireplace?In fact, a faint gas smell is an unavoidable consequence of using gas fireplace logs. In a gas ventless fireplace, oxygen is provided by the air in your home. If that air contains impurities, those impurities are drawn in with the oxygen and can produce odors which are amplified by the flame.Also, do gas fireplaces give off carbon monoxide? Yes, gas fireplaces are one potential cause of carbon monoxide poisoning. While there are many potential sources of such exposure, including certain appliances and devices, motor vehicles and wood stoves, gas fireplaces are a common culprit to be aware of. Also question is, are fumes from gas fireplace harmful? Gas fireplaces are generally considered cleaner than traditional wood-burning fireplaces, but they can also pollute indoor air quality if not properly vented. Toxic gasses emitted include deadly carbon monoxide and nitrogen dioxide — a gas particularly harmful to those with asthma.How can I tell if I have a gas leak in my fireplace? The logs connect to a gas supply line at the side of the fireplace and run on either natural gas or propane. Gas leaks in fireplace logs are dangerous. Open any screens or doors in front of the fireplace opening. Sniff the air around the fireplace to determine if it smells like rotten eggs.