 In April 2010, some environmental organizations called on the NRC to investigate possible limitations in the AP1000 reactor design.These groups appealed to three federal agencies to suspend the licensing process because they believed containment in the new design is weaker than existing reactors.In April 2010, Arnold Gundersen, a nuclear engineer commissioned by several anti-nuclear groups, released a report which explored a hazard associated with the possible rusting through of the containment structure steel liner.