One of the most important parts of this piece by @Emily_Unglesbee is this: it will be harder for states to place tighter restrictions than in previous years. https://www.dtnpf.com/agriculture/web/ag/crops/article/2020/10/27/epa-approves-three-dicamba-federal

Many people are going to criticize this. When I first heard EPA was considering this step, I also was opposed. But I spoke with an EPA scientist who explained why it was being considered, and it made perfect sense. So here's the deal:

24(c) process was designed for label *expansion* by states. It allows a state to allow uses that are not on the Federal label. For example, Wyoming might allow a soybean herbicide to be used in fallow or on a different kind of bean.

The 24(c) label works basically as supplemental labeling. You can apply according to the 24(c) expanded use if you have the expanded label. It basically acts as an amendment to the product label attached to the product. The label is the law, and you must have the label.

And this 24(c) system works well for label expansions - a user can find the supplemental label, print it out, take it to the field and spray according to the expanded use requirements. Easy to enforce - the applicator can prove the application is legal because s/he has the label.

But things get tricky, especially with respect to enforcement, if using the 24(c) process for *restricting* the Federal label.

The label is the law, and the label is physically affixed to the product. To use the expanded 24(c), just bring the label with you, and it's legal.

But who is responsible for a more *restricted* 24(c) label? The way the regulation is written, if the 24(c) isn't with the product, then the applicator is held to the product label. The Federal label, affixed to the product.

A strong case could be made that it would be impossible to legally enforce a more restrictive 24(c) label, if they were following the federal label. So the 24(c) process isn't a good process for imposing tighter restrictions on a pesticide. That's not what it was designed for.

So if you want EPA/states to be able to actually enforce more restrictive labels, then explicitly disallowing use of 24(c) for this purpose is probably a good move in the long run.
/thread

Addendum: text of FIFRA section 24. Part (c) is explicitly titled "additional uses"