There are multiple security clearances.
The colors can be used like in CTA-033 (the orange bar that says level 3)
Level 1:Green
Level 1 clearance is given to people non-essential to research for the corporation. For example, janitorial staff are given Level 1 clearance, they don't require any knowledge of any anomalies.
Level 2: Yellow
Level 2 clearance is given to scientists who require direct knowledge of anomalies for research purposes. Most scientists have Level 2 clearance.
Level 3: Orange
Level 3 clearance is given to security guards, and intermediate level scientists who require knowledge of Dangerous class objects for research.
Level 4: Red
Level 4 clearance is given to advanced level scientists and to all people in military forces. Level 4 clearance staff are given knowledge of Lethal class objects for research.
Level 5:Black
Level 5 clearance is given to administrative personnel and veteran level scientists. Personnel and staff with Level 5 clearance have knowledge of all anomalies that the corporation has encountered.
JD Personnel
JD Personnel are basically the lab rats of the corporation, they are used to test on CTAs.