外国工程师是否需要考特种作业操作证？

Here is a big trouble for me.

We have nearly 90 foreign engineers for electricity commissioning work in the project sites in China. These engineers signed the contract with enterprise headquarter in Germany, and are delegated to China for project support and service. They all received perffessional trainings and certificates from our enterprise headquater.

My question is ----

Should they have to pass the Special Operator examination and get the certificates from governmental department in China? If they don't have this kind of certificate, will our enterprise in China take over the non-compliance result and responsibility?

Any one has this kind of experience?