A Class A Operator must oversee and assume responsibility for every regulated UST facility assuring compliance and documentation thereof.  Class B Operators assume an on-site role, overseeing safe, compliant operations of UST facilities.  These A and B roles are often combined and may be contracted to a third party provider.  The Class C Operator is usually a daily, on-site employee responsible for responding to alarms and emergencies.  All UST facilities must have a certified class A, B and C operator.