Composting the material will reduce any possible toxicity.

Here is a link that might be useful: Walnut Toxicity

I have not seen any sign of a problem with the compost made when my Black Walnut leaves are mixed in. Now if I take all the leaves that drop from one of the BW trees, shred them and plunk just those leaves down in an area I will see the Quack Grass die off and the Perennial Rye grow abundantly, but I've not done that anyplace else besides where Quack Grass is and the compost is always a mixture of many leaves.
I have never tried to measure how much of the Junglone is in the leaves but I'd suspect not much.

Thanks for the info. I did a Google search before I posted the question and the information on this issue was all over the place. Some sites said the leaves are fine to use while other strongly advise against it.
David

When I researched it awhile back I found that the roots are highest in juglone and there is not so much in the leaves. If composting a mixture of leaves I wouldn't worry about it.

The link below I believe is very good. It states what's can grow with out being effected by juglone and things that are effected by junglone. But it also states that composting leaves only takes a few weeks and there is basicly no trace of juglone and the bark can be composted for 6 months with no trace of juglone and can be safe for plants that are sensetive to juglone.

Here is a link that might be useful: cans and can't grow around black walnut

As with other leaves, chew them up and give to the compost pile. Just don't pile black walnut leaves onto a garden where such toxicity can influence.