I haven't seen this particular complex, but a lot of new apartment construction in the area has a basement parking garage. You'd think it would have enough ventilation and have enough natural circulation that this would be even more unlikely. Unless they shut of the fan because no one was leaving during covid.
I moved to another apartment building for the two years after that, and continued to have measurable AQ issues because the dryer, bathroom, and kitchen vents were flowing in reverse due to a poor building ventilation design that used a single central vent shaft and didn't adequately account for wind or the height of the building. I was on a side and floor of the building that had negative relative pressure much of the time.
Air isn't a perfectly homogenized uniform fluid -- there are very localized effects, and because it's often invisible, those local effects are often dismissed.
IMO the only sane and responsible way to develop apartments in a challenging environment (by a highway, by a fire or bbq environment, in an area where weed is legal, or on a toxic site) is for every single unit to have its own air handling system to maintain air quality and positive pressure in that individual unit.
> The Santa Clara Square project encompasses approximately 93 acres
The challenge with these stories is that they rely on vague details to create an appearance of plausibility. The fact that a tank containing some substance exists somewhere in a 93-acre property would not normally be credible cause to believe that someone’s symptoms in a 3rd story apartment are the result of the soil.
Again, to emphasize: I am not doubting that this person is suffering real symptoms. I think it’s a mistake to focus on the soil or mysterious tanks in unknown location as the cause to the exclusion of other possible causes.