Conservationists criticized US President George W. Bush's decision to exempt the Navy from an environmental law so it can continue using high-power sonar in its training off California - a practice they say harms whales and other marine mammals. The president's action will not allow the anti-submarine warfare training to go forward because an injunction is in place, but the Navy believes it will significantly strengthen its argument in court. However, late Wednesday, the appeals court sent the issue back to US District Court to consider first. The White House said Bush signed the exemption Tuesday while traveling in the Middle East. In his memorandum, Bush said the Navy training exercises "are in the paramount interest of the United States" and its national security. Peter Douglas, the executive director of the California Coastal Commission, which joined in the lawsuit to give the marine mammals greater protections from sonar, called the exemption unprecedented in California. "I'm not surprised at all," he said. "It's typical for this Republican administration to ignore environmental protections under the banner of fear."