You read that incorrectly..

If you invest in one house, you have the added risk of everything in one basket.Also, it's incorrect to say that the yield per investment is necessarily going to go down because you split into multiple pots. 

These can be sticky transactions and the LAST thing you want is to take on ANY liability for what might or might not be in the dirt or ground water.Im also fairly certain that you can not put any food uses (or residential uses) on contaminated sites but that might be incorrect.

@RaKell Adams, At this time in a maturing market it's very natural to move into a more defensive posture to protect those gains. 

Perhaps I am reading the law incorrectly or others are in the game and not playing by the rules.

Reasons as to why this is incorrect?  

@Alex Day, the information above is incorrect. 

I, possibly incorrectly, thought you might be looking at one of these types of homes. 

This is not a complex matter, but if it's done incorrectly, it can create unintended negative consequences down the road for your folks, you and your sibling.  

But I would have already talked with him about these issues if I knew he was lying about showing it or if I noticed the status was incorrect.