I wouldn't see any real issues with using it, once it's mixed in structurally and dried out a little.
However, if you're not sure about whether it might have had the aminopyralid herbicide weedkiller in, then plant a few bean seeds in it and let them grow before applying it to the garden. If the beans grow healthily without distorted foliage then it's fine. Better to delay using it than put it on the ground and then have contamination issues.