HOUSTON, Feb 6 (Reuters) - The United Steelworkers union (USW) adopted ‌a national ​agreement negotiated with ‍Marathon Petroleum ⁠for ⁠use in contracts ‌between ​30,000 oil industry workers ⁠and ‍their ​refineries and chemical plants, the union ‍said in a statement posted on-line. 

The 4-year ​agreement ‍will lift pay for ​the hourly workers by 15%. It also provides a $2,500 ​signing bonus for USW represented employees.