The union approved the occasional use of temporary workers by U.S. automakers during the last contract talks in 2015, when the two sides agreed to gradually phase out the existing two-tier wage structure.
Temporary workers represent about 20% of the workforce at Japanese automakers in the United Sates and are paid an average of $50 an hour, according to figures compiled by Automotive News and the Center for Auto Safety.
In comparison, GM pays its workers an average $63 an hour.