One of the many paths to immigration to the United States is through permanent employment with a U.S. employer sponsoring a immigration petition, Form I-140, Petition for Alien Worker. Before submitting the immigration petition, the employer must pursue a labor certification request with the Employment and Training Administration (ETA) of the Department of Labor. Once the certification is approved, the employer sends the certification with his Form I-140 submission to the Unites States Citizenship and Immigration Services (USCIS). Upon approval of the petition at USCIS, the petition enters the queue at the State Department where visa numbers are issued. The issuance of visa numbers is prioritized based on the type of worker applying for legal permanent residence. High priority workers, such as those with extraordinary ability in the sciences, arts, education, business or athletics, those who are outstanding professors or researchers, or managers and executives subject to international transfer to the U.S., are assigned an EB-1 classification. EB-2 is reserved for professionals with advanced degrees or persons with exceptional ability, such as those with exceptional ability in the sciences, arts or business; those with advanced degrees; and those who will practice medicine in underserved areas of the U.S. EB-3 is reserved for skilled or professional workers not meeting the criteria for EB-2, including professionals with bachelor's degrees, skilled workers with at least 2 years of experience and unskilled workers. A separate application procedure is reserved for special immigrants under the EB-4 classification, including religious workers and employees and former employees of the U.S. Government abroad. EB-4 workers are subject to a special application process through Form I-360, Petition for Amerasian, Widow(er) or Special Immigrant. Once the visa number is issued, immigrants are able to adjust their status to legal permanent resident either while within the U.S. or abroad through a U.S. Consulate.