(Francisco Kjolseth | The Salt Lake Tribune) Big West Oil refinery in North Salt Lake is pictured on Jan. 6, 2023. It's been almost six years since Gov. Gary Herbert and the Utah Legislature came up with an incentive to encourage Utah's refineries to produce cleaner Tier 3 gasoline. A Big West spokesperson says the company is committed to deliver the cleaner gasoline to the Utah market by 2024.