The latest attempt by Congress to overhaul the U.S. patent system has run into a new hurdle, with organized labor expressing concern that the legislation could damage U.S. leadership in innovation and the nation's ability to create new jobs. The reform measures, strongly backed by the information technology sector, aim to curtail the growing number of patent infringement lawsuits and place monetary limits on damage awards. But biotech companies and many manufacturers fear the changes will discourage innovation by weakening the value of their patents. In recent letters to congressional leaders, AFL-CIO, United Steelworkers, and the International Federation of Professional & Technical Engineers contend the Patent Reform Act of 2007 will weaken the existing intellectual property regime, making it easier for foreign firms to copy patented processes and products. The unions are troubled by provisions that would create new opportunities for challenging the validity of patents after they are granted and that would alter the current system for calculating damages for infringement. "These bills would allow an endless loop of legal challenges after patents are awarded that will make it more difficult for U.S. patent holders to prevail against frivolous challenges often initiated by our foreign competitors," says the letter from United Steelworkers.