In a letter on the company's Web site from Bob Mansfield, senior vice president of Hardware Engineering, the company acknowledged that it has "recently heard from many loyal Apple customers who were disappointed to learn that we had removed our products from the EPEAT rating system." He said that "this was a mistake," and all "eligible" Apple products are immediately back in EPEAT.

What Products Are 'Eligible'?

A key question is the meaning of the term "eligible." Some of the Apple's products, such as the new MacBook Pro Retina laptop , may no longer be eligible because the battery and screen glass are glued to the casing. EPEAT requires that components with toxic materials, such as batteries, must be able to be disassembled from recyclable components.

Additionally, EPEAT does not currently cover smartphones or tablets.

Mansfield, who is soon retiring, said the company's commitment to protecting the environment "has never changed," adding that "Apple makes the most environmentally responsible products in our industry."

He cited Apple's leadership in removing harmful toxics from its products, its reporting of greenhouse gas emissions for every product it makes, and its exceeding the Energy Star 5.2 efficiency standards for the entire product line.

Mansfield suggested that the IEEE 1680.1 standard, on which EPEAT is based, might be strengthened to include better energy efficiency metrics.

'Somebody Looked Around'

Apple was a participant in the creation of the EPEAT standard in 2006, which was formulated by a group of technology companies, environmental organizations, and federal agencies. EPEAT is managed by an independent, non-profit organization.

The organization said that its rating offers a chance for participating electronics manufacturers to "showcase and validate their greener design initiatives, cleaner production and customer support services." It added that the standard is "more than simply a product rating," because it is a "community effort" to define and maintain best practices for environmental sustainability for electronic products.

Apple was facing a major backlash from some of its most dedicated customers. Shortly after it announced that it was abandoning EPEAT, the city of San Francisco said that its 50 departments would no longer be allowed to buy computers or displays from the nearby company, because of the city's environmental standards.

The huge University of California also announced it was considering such a decision, and many other universities, corporations, governmental entities, and other customers might have reacted similarly.

Charles King, an analyst with industry research firm Pund-IT, said that "somebody at the company looked around" and saw the potential loss of sales from steady and large customers. He added that many IT departments might also have thought twice about buying Apple products without EPEAT certification.