I might be mistaken, but I think that so long as the machine has all the safety features that were present when the machine was made, you can still use it.
It is still legal in Missouri to drive without a seat belt; providing that the vehicle you are driving was not equipped with one from the factory. I think that there may be some exceptions to that rule, but I don't know of any.
Shucks, you can still use DDT to control the mosquitoes in your pond, or lindane to control your cattle's insect problems, or chlordane to protect your house from termites. You'd better be ready to prove that you purchased it legally and used it according to the label!
They were never made illegal to use, they were just banned for production and re-sale in the US. Dealers only had a limited time to sell the product once taken off the market, and then the supply dries up.
Exceptions seem to be the government environmental regulations about using various products, like 1/2 the diesel equipment in California.