Why Ethanol-Free Gas Is Hard to Find at Costco in Hawaii

Costco Wholesale has begun selling gasoline containing ethanol at its fuel stations on Oahu, Hawaii, marking a shift from its previous ethanol-free offerings. The change, which took effect on Monday, April 27, 2026, applies to regular 87-octane gasoline at Costco locations in Kapolei and Waipio, according to customer reports verified by News Directory 3.

Change Confirmed by Customers and Attendants

Multiple customers reported the transition after noticing the removal of decals on fuel pumps that previously stated the gasoline was ethanol-free. One Kapolei Costco attendee confirmed the change, telling a customer that the company was complying with a “President’s mandate” requiring ethanol blending in gasoline. While the exact federal or state mandate referenced was not specified in customer accounts, the shift aligns with broader regulatory trends promoting renewable fuel standards.

A Reddit user shared their observation on April 27, 2026, stating, “Costco gas on Oahu now has ethanol in it,” and noted they had never seen ethanol-free gasoline at Costco’s Kapolei or Waipio locations prior to the change. The post, which served as the discovery source for this report, reflects growing consumer awareness of the fuel composition shift.

Historical Context: Costco’s Ethanol-Free Gasoline in Hawaii

Until recently, Costco’s regular 87-octane gasoline in Hawaii was marketed as ethanol-free, a distinction highlighted by prominent decals on fuel pumps. This set Costco apart from many mainland U.S. Retailers, where ethanol-blended gasoline (typically E10, containing 10% ethanol) is standard due to federal renewable fuel mandates. Hawaii’s unique fuel market, which relies heavily on imported petroleum refined locally by Par Pacific in Kapolei, had previously allowed for ethanol-free options at select retailers, including Costco.

Customer discussions on social media platforms, including Reddit and Facebook, have long noted Costco’s ethanol-free gasoline as a key differentiator. A 2021 Reddit thread, for example, highlighted the presence of ethanol-free stickers on Costco pumps in Honolulu, while a 2023 thread confirmed that most gasoline sold in Hawaii was refined by Par Pacific and speculated about the ethanol content of various fuel grades. However, these discussions predated the recent change, which appears to be a direct response to updated regulatory or corporate policies.

Why the Shift Matters for Consumers

The introduction of ethanol-blended gasoline at Costco’s Oahu locations has implications for vehicle owners, particularly those with older cars, small engines, or vehicles not designed for ethanol-containing fuel. Ethanol, while a renewable resource that can reduce greenhouse gas emissions, has several drawbacks that concern some consumers:

• Reduced fuel efficiency: Ethanol contains less energy per gallon than pure gasoline, which can lead to a 3-4% decrease in fuel economy.
• Water absorption: Ethanol is hygroscopic, meaning it attracts and absorbs water. Over time, this can lead to phase separation, where water and ethanol separate from gasoline, potentially damaging fuel systems.
• Corrosion risks: Ethanol can be corrosive to certain materials, such as rubber and plastic components found in older fuel systems, leading to long-term maintenance issues.

For consumers who prioritize ethanol-free gasoline, the change at Costco may prompt a shift to other retailers that continue to offer such options. However, the availability of ethanol-free gasoline in Hawaii has been declining as regulatory pressures and cost considerations push retailers toward ethanol-blended fuels. Costco’s decision may reflect broader industry trends rather than an isolated corporate choice.

Regulatory and Economic Factors Behind the Change

While customer reports suggest the change is tied to a “President’s mandate,” the specific regulatory driver remains unclear. In the United States, the Renewable Fuel Standard (RFS), established by the Energy Policy Act of 2005 and expanded under the Energy Independence and Security Act of 2007, requires the blending of renewable fuels like ethanol into the nation’s gasoline supply. However, Hawaii has historically had exemptions or modifications to these requirements due to its unique fuel market and reliance on imported petroleum.

Costco’s decision may also be influenced by economic factors. Ethanol is typically less expensive than pure gasoline, and blending it into fuel can reduce costs for retailers. A 2024 Facebook discussion among Hawaii residents noted that ethanol costs about 30% less than gasoline on the mainland, with even higher cost differentials likely in Hawaii due to the state’s reliance on imported fuel. For a large retailer like Costco, which operates on thin margins and prioritizes cost efficiency, the financial incentive to switch to ethanol-blended gasoline may be significant.

Consumer Reactions and Alternatives

The shift has sparked mixed reactions among Hawaii residents, particularly those who relied on Costco for ethanol-free gasoline. Some customers expressed frustration on social media, citing concerns about engine performance and long-term vehicle maintenance. Others acknowledged the inevitability of the change, given broader industry trends and regulatory pressures.

For consumers seeking ethanol-free gasoline, alternatives in Hawaii may be limited but not nonexistent. Some independent fuel retailers and marinas continue to offer ethanol-free options, though these are often priced at a premium. Consumers with small engines, such as those in boats, lawnmowers, or classic cars, may need to seek out specialized fuel suppliers or additives designed to mitigate the effects of ethanol.

What’s Next for Costco and Hawaii’s Fuel Market

Costco has not issued a public statement regarding the change, leaving customers to rely on anecdotal reports and observations from fuel station attendants. The company’s decision to introduce ethanol-blended gasoline at its Oahu locations may signal a broader shift in Hawaii’s fuel market, particularly if other major retailers follow suit. If regulatory pressures continue to mount, ethanol-free gasoline could become increasingly scarce in the state, further limiting options for consumers who prefer or require it.

For now, the change at Costco serves as a reminder of the evolving landscape of fuel regulations and consumer choices. As renewable fuel standards expand and economic pressures influence corporate decisions, Hawaii’s unique fuel market may continue to adapt, with implications for both retailers and vehicle owners.