Trying to overcome a possibly crippling court decision, the Environmental Protection Agency hopes to have a proposal by early next year on new radiation exposure limits at a proposed nuclear waste site in Nevada. Jeffrey Holmstead, chief of EPA's air and radiation programs, told a panel of scientists this week that a wide range of options is being considered that would not require Congress to intervene in the politically charged issue. The future of the waste project at Yucca Mountain in the Nevada desert was put into jeopardy when a federal appeals court rejected an EPA radiation exposure standard in July that was tied to 10,000 years into the future, even though some of the waste will be at its most dangerous thousands of years later.