At EPA, Andersen's responsibilities included analysis of regulatory impact, cost, and trade, technology co-operation, and sector projects in halons, foams, mobile air conditioning, and military uses. Over his tenure he pioneered EPA's voluntary approaches to ozone layer protection including the phase-out of chlorofluorocarbon(CFC) in the manufacturing of food packaging, the recycling of CFC from vehicle air conditioning, the halt to testing and training with halon, and the accelerated CFC solvent phase-out in electronics manufacturing. Andersen also brought Soviet authorities together with NASA scientists and EPA senior managers to gain agreement for US Total Ozone Mapping Spectrometer (TOMS) be carried to space on a Soviet Meteor-3 satellite(1994) rocket in order to overcome loss of access to space (resulting from the Space Shuttle Challenger accident); he founded and managed the first EPA international awards, the U.S. EPA Stratospheric Protection Awards and Climate Protection Awards; and was EPA Liaison to the U.S. Department of Defense (DoD) on stratospheric ozone and climate, chairing several DoD committees on solvent validation, aircraft maintenance, manufacturing rockets without ozone-depleting substances, and certifying the Joint Strike Fighter for particulate emissions.