  To compute the local cohomology of powers of edge ideals one needs to know
their saturations. The saturation of the second and third powers has been
described in terms of the graph in [13] and [10]. In this article, we give a
combinatorial description of the generators of the saturation of the fourth
power. As a consequence, we are able to give a complete classification of the
associated primes of the fourth power of edge ideals in terms of the graph.
