Yes its a risk, it has been covered a lot here for many years, see this forum post for example
http://www.charlesdowding.co.uk/forums/general-gardening/vegetables/manure-and-aminopyralid
I would do a germination test as described eg sow peas, broad beans undercover, you know within about three weeks.
The words we use to describe these things are interesting – normal manure for me would be organic!