A Cooperative Research Program conducted through SAE International to investigate the safety and environmental performance of a new refrigerant for mobile air-conditioning systems announced that HFO-1234yf can be used as the global replacement for R-134a. An earlier SAE research program found HFO-1234yf to be the most promising of several potential replacement candidates. In the latest research program, a two-year affair that cost $1.3 million in cash and another $1 million plus from in-kind use of property and personnel among program sponsors, HFO-1234yf was put through various types of safety and environmental tests by several third-party labs around the world. The testing confirmed that the substance is an environmentally friendly refrigerant suitable for use in direct-expansion air-conditioning systems. HFO-1234yf has a Global Warming Potential of 4; the figure for R-134a is 1430. The European Union is phasing out R-134a. Phaseout of R-134a is not mandated in the U.S. The U.S. EPA recently released a proposal to allow use of HFO-1234yf. Sponsors of the SAE research program include 15 global automakers and 18 Tier 1 suppliers.