I thought that was standard? (Movers not transporting chemicals.)

We have hazardous/chemical waste sites across the Metro for them to take the chemicals to for disposal.

That seems common.  A good moving company would likely have recommendations on how to handle or an excellent real estate agent/broker will be able to suggest alternative methods of "moving".  

This is a known rule so I share they need to have a disposal plan or offer them to the buyer as a "starter kit" along with the leftover paint.

That's industry standard here and people either take it themselves, throw it out or donate it to a neighbor who can use it.

Dispose of the chemicals following local regulations.

I've never heard of such a thing Will Hamm 

Will,

I would say this is Standard Operating Procedure...what is seller doing with chemicals?  Do they a lab in their home?  A

Get a hold of the city to see when they have a disposal date.

I wouldn't tell them anything... their moving company is their business and their choice. But as far as I know, no moving company wants to move chemicals.... it's a hazard.

This is standard, tell them to get with it. In case any of that stuff spills & ruins their stuff. It's common sense.

If you're storing hazardous chemicals, you have to move them in your own vehicle or dispose of them prior to the move. Moving them in your own vehicle may cause problems interstate.

Most moving companies maintain a list of items they won't or can't transport.

Here's a standard example from Able's website. https://ablemoving.com/resources/safety-tips-what-not-to-pack/

What your question just said...perhaps the seller has a solution (pun)

no moving companies will transport any chemicals.... 

they need to call a company that disposes of chemicals and hazardous waste..... must be removed from property by a company that specializes in that..... 

Moving companies are not, nor have they ever been, companies that deal with hazardous waste.  Most cities have sites for people to drop off chemicals, hazardous waste and biohazards. 

Take them to a disposal site. Been that way for years!

I suggest that people give away EVERYTHING that is not sentimental.

Cheaper to rebuy it than to move it.