  An isolating set in a graph is a set $X$ of vertices such that every edge of
the graph is incident with a vertex of $X$ or its neighborhood. The isolation
number of a graph, or equivalently the vertex-edge domination number, is the
minimum number of vertices in an isolating set. Caro and Hansberg, and
independently \.{Z}yli\'{n}ski, showed that the isolation number is at most
one-third the order for every connected graph of order at least $6$. We show
that in fact all such graphs have three disjoint isolating sets. Further, using
a family introduced by Lema\'{n}ska, Mora, and Souto-Salorio, we determine all
graphs with equality in the original bound.
