I wish I had more to point at rn but, hemp crops can help pull toxins from soil. Other crops too , can help with a "brown zone" but hemp (and it's cousin) get more press.
https://usfblogs.usfca.edu/sustainability/2022/02/03/mycorem...
Normal toxic site cleanups that I have read about usually involve at minimum replacing topsoil to a depth of several feet.
[1] https://www.novus-environmental.co.uk/blog/why-is-hazardous-...
This material is for industrial hemp, making rope and fabric and things.