Dismissing her symptoms as completely fabricated is ridiculous but I think it's entirely reasonable to dismiss her explanation for them out of hand because it is entirely on-par with cell-tower crazies spouting off nonsense about things they don't understand.
She was on the third floor, no one else is having symptoms, lead and arsenic contamination beneath a foot of dirt and a big thick concrete foundation is never going to plausibly cause very high VOC levels only in one third floor apartment. She even dismisses expert opinions that disagree with her idea as "some expert wordsmithing and spin". She even claims that it's contaminated the tap water, as if it must just come from the groundwater.
I find the claim that there's a high VOC level in an apartment causing numerous health problems completely reasonable. It's the blatantly ridiculous leap of blaming remediated soil contamination that makes me dismayed. Quite frankly it makes people dismiss real environmental health problems by throwing in that nonsense along with it.
There's tons of valid explanations here, maybe when the flooring was replaced they went with a different supplier for that faux wood laminate and it's off gassing formaldehyde. Maybe the carpet in some part of the apartment had a similar issue. Maybe the drywall had to be replaced in that unit in the past and it's contaminated akin to the imported Chinese drywall back in the 00s. Maybe the paint stripper the apartment complex maintenance worker used was based on DCM and he accidently tipped over the can and they just said "screw it, we're putting new flooring over it anyways".
There's a thousand different valid explanations here, her explanation is nowhere on the map.