Summary: Interest is widespread in the entry of alien workers into the U.S. workforce. Some view foreign workers as a solution to labor problems, while others see them as a threat to the job security of Americans. About 136,000 aliens became employment-based immigrants between 1984 and 1989, with another 293,000 temporary alien workers admitted during the same period. GAO studied two classes of immigrants: (1) H-1 nonimmigrants, aliens "of distinguished merit and ability" who are admitted temporarily to do work of "an exceptional nature," and (2) L-1 nonimmigrants, aliens employed by an international firm who are entering the United States to work for that company as a manager, executive, or a specialist in a particular field. GAO's research suggests that thousands of permanent jobs in the U.S. are being filled by a succession of highly skilled temporary alien workers in fields like engineering and science, while in the health care industry 85 percent of temporary alien workers, mostly nurses, occupied jobs intended to be permanent.