Group Leader In Matters Of Safety (GLIMOS)
An experiment collaboration consists of a number of teams (or groups), from different research institutes, each having its own hierarchical order.
In all matters concerning safety this order is overridden by the CERN safety organisation, in the first hand represented by the GLIMOS ( = Group Leader In Matters Of Safety). There is a GLIMOS nominated for every physics experiment at CERN.
The GLIMOS is the most important person for the safety of his experiment and has complete authority over personnel and equipment in all matters that concern safety of the experiment, independently of to what home institute the personnel or equipment belongs.
You can always turn to him for information and advice. If you have had an accident or, more generally, want to make a remark about anything that concerns safety, it is to your GLIMOS you should address yourself.
Your legal situation when working at an experiment at CERN
If you work in an experiment collaboration at CERN you will have signed a contract of some kind. This implies that you now work under the authority of the Director General of CERN and that you have to conform to the CERN rules of safety, independently of whatever rules are in force at your home institute.
You are expected to inform yourself about the safety rules at CERN.