We construct a localization for operads with respect to one-ary operations
based on the Dwyer-Kan hammock localization. For an operad O and a sub-monoid
of one-ary operations W we associate an operad LO and a canonical map O to LO
which takes elements in W to homotopy invertible operations. Furthermore, we
give a functor from the category of O-algebras to the category of LO-algebras
satisfying an appropriate universal property.