AUSTIN (KXAN) — No, you’re not imagining it. There is a natural gas-like smell in the air in Austin Thursday, but you don’t need to call the fire department. 

Austin fire officials say the “Luling Effect” is back and worried Austinites have been calling to report the smell.

The odor comes from the oil fields in Luling and Lockhart and it is normal for this time of the year. When we have a cold, still night, that sulfur smell collects at the ground instead of dissipating like normal, so in the morning the wind brings up the smell and it spreads across the city.

In a tweet Thursday morning, officials said they received calls from the area east of Interstate 35 from south Austin to Pflugerville. 

Fire officials are still encouraging people to call 911 if they smell natural gas inside their homes to be safe.