Since 2003, Yudean Group has carried out the integrated execution of the three standards of "ISO9000, ISO14000 and OHSMS18000", and the NOSA five-star safety, health and environment protection management, devoting us to the construction of a long acting mechanism for production safety. So far, 26 power plants have passed the certification for the three standards，and 9 power plants have passed the NOSA star grading. Among them，there are 5 five-star ones, 2 four-star ones and 2 three-star ones.