I saw this article at BoingBoing, and had to look it up.
From Wikipedia:
The Aroma of Tacoma, also known as the Tacoma Aroma, is a putrid and unpleasant odor associated with Tacoma, Washington, United States.[1] The smell has been described as similar to the odor of rotten eggs.[2] The odor is not noticeable throughout the city, but is rather concentrated in the Tacoma tideflats and is frequently smelled by motorists traveling that section of Interstate 5.[2]
Crossposted from til@lemmy.world: https://lemmus.org/post/23788650
I remember it well in the 70s, even in town. I recall the theory at the time was that the sulfur smell was from the pulp mills that were in operation at the time. But those are now gone, and the aroma remains, though it's less intense and more localized now.