Here is another interesting Top Tier "requirement"
For a company to claim Top Tier compliance, all retail outlets selling the gasoline brand must be compliant. So if say SHELL is claiming compliance all SHELL stations nationwide must be compliant. Each store or region can not independantly choose to be Top Tier or not.

Here are the current retailers that are listed with Top Tier as compliant:
QuikTrip
Chevron
Conoco
Phillips
76
Shell
Entec Stations
MFA Oil Company
Kwik Trip/Kwik Star
The Somerset Refinery, Inc.
Chevron-Canada
Aloha Petroleum
Tri-Par Oil Company
Shell-Canada
Texaco
Petro-Canada
Sunoco-Canada