Name-brand stations make up nearly half of all gas stations nationwide.
Duffy said reaching the U.S.'s objectives "will play out" over several weeks.
U.S. Central Command launched "Project Freedom" to reopen the Strait of Hormuz.
The convenience and fuel retailer is offering up to 40 cents off per gallon.
"This is not the way I thought my retirement was gonna turn out," one said.
