NOVELTY - A foam-forming composition (C1) comprises a foamable liquid polymer, a curing agent for the polymer, a blowing agent and a soluble, solid viscosity modifier.    USE - For forming foam such as microporous, open-cell foam of hierarchical structure used for removing oil from body of water with concomitant recovery of oil, or to reversibly absorb oil (claimed), where body of water e.g. oil spill, where open cell foams have many applications including bioscaffolds, high surface area catalysts, filters, battery-capacitors and fuel cell electrodes, vibration/acoustic dampers, thermal insulation, and sorbents; also useful in maritime oil spill clean-up operations.    ADVANTAGE - The composition improves mechanical and physical properties. The composition provides combination of porogen/filler leaching and liquid blowing agent techniques, which is capable of creating hierarchical polymeric foam. The composition forming the open-cell foam of hierarchical structure is sufficiently strong and resilient as to be capable of being compressed between mechanical rollers or other compression apparatus and upon release from compression return substantially to its original form. The open-cell structure of the resulting foam, in addition to its intrinsic oleophilic-hydrophobic surface property, low glass transition temperature and chemical resistance against low molecular weight organic compounds all combine to make the foam product capable of reversibly absorbing oil (petroleum-based, as well as vegetable oil), while repelling water. As a result, in comparison to a material that absorbs oil and water, much less foam is needed to absorb the same volume of oil. In addition, the foam may be reused multiple times. The composition can be prepared rapidly at low cost, can be reused, is scalable and exhibits excellent thermal stability at both low and high temperature.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a microporous, open-cell foam (F1) of hierarchical structure, comprising the cured composition (C1), in which the pores are randomly distributed throughout the foam, and the foam is effective to reversibly absorb oil;    (2) a process (m1) of making a polymeric microporous, open-cell foam of hierarchical structure involving (a) preparing a first mixture of a volatile liquid blowing agent and a soluble, solid viscosity modifier; (b) mixing the first mixture with a foamable liquid polymer to which a curing agent has been added either before or after the mixture of the first mixture with the polymer to form a second mixture; (c) heating the second mixture at 50-95 degrees C to produce a cured, compressible cellular foam; and (d) treating the cured foam with a solvent effective to remove from the foam structure the solid viscosity modifier and form intercellular passages in the foam; and    (3) a method (m2) for removing oil from a body of water with concomitant recovery of the oil, involving contacting the oil with the microporous, open-cell foam (F1); causing oil to be absorbed by the microporous, cellular foam; and separating and recovering the oil from the foam.