Environmental policy of the United States from the sun. Chlorofluorocarbons (CFCs), which were used beginning in the 1930s in a number of important areas, were determined in 1974 to be responsible for much of the depletion of the ozone layer. Four years later, the EPA and FDA banned CFCs in aerosol cans. As research in the 1980s indicated that the problem was worse than before, and revealed a controversial massive hole in the ozone layer over Antarctica, three international agreements were made to reduce the ozone-damaging substances- the Vienna Convention, the 1987 Montreal Protocol, and a third agreement in 1990 in London. In the United States,
Wiley protocol at separate times throughout the period. The protocol is promoted as differing from conventional hormone replacement therapy in several ways: The protocol also includes a follow-up program to monitor the serum of the bioidentical hormones. Wiley has stated that in her opinion, the most important aspect of the protocol is the specific schedule and levels of the hormone doses rather than their bioidentical nature. A patent was granted for the protocol in 2011 for the specific blend of hormones and dosing method. Concerns have been raised that serum levels may not be an acceptable marker for transdermally administered hormones, that