MANILA, Philippines — The World Wide Fund for Nature (WWF) Thursday urged the public to patronize local ethanol products, stressing that these would help to usher the automobile industry and the economy into a cleaner and greener era.

The WWF disputed claims that ethanol corrodes vehicle gas tanks, fuel injectors and carburetors, saying that all types of automotive gasoline have corrosive properties.

“Ethanol in itself is non-corrosive. The real culprit is water, which can contaminate a gas tank. The ethanol in the gasoline mix then absorbs the water, which accumulates and occasionally causes corrosion,” said WWF climate change and energy program director Yeb Saño.

The group said that car manufacturers have already addressed the issue of corrosion from water by using materials like polymer, rubber neoprene or Teflon composites that are more durable and rust-resistant than earlier versions, in newer car models.

“Most—but not all—petroleum companies also offer fuels with added corrosion inhibitors, which retard corrosion and protect gas tanks. This blend is based on a treat rate, the optimal ratio for various fuels and engines,” WWF said.

According to the WWF, ethanol is a high-octane and water-free alcohol derived from sugarcane, corn and other locally sourced crops. Blended in small amounts with regular gasoline, it could provide the transportation sector with a cheaper and cleaner fuel alternative—without the need for expensive car modifications, it said.

Press reports earlier quoted some energy industry leaders as saying that the current ethanol-blended gasoline is highly corrosive and may damage certain parts of a vehicle’s fuel system.

According to WWF, the Department of Energy has already laid out stringent rules, guidelines and accreditation systems for oil producers and distributors to ensure the quality of ethanol-blended gasoline.

Under the Biofuels Law, the government has mandated the pre-blending of 5 percent ethanol in local gasoline starting last February. This will be increased to 10 percent by 2011.

But since last year, most oil companies have already been selling the E10 (gasoline blended with 10 percent ethanol), ahead of what the law requires.

The WWF has been pushing for the use of biofuels because unlike fossil fuels, ethanol is practically inexhaustible since crops like sugarcane, corn and sweet sorghum can be grown and harvested in a sustainable manner.

“Long-term sustainability requires far more than embracing biofuels. Mandatory fuel efficiency standards and a shift from roads to much-more sustainable rail networks are crucial to success,” said Saño.