Apple has once again been singled out for using toxic materials in its products, despite recent attempts to improve its environmental policies.

The latest round of criticism, which follows hot-on-the-heel's of Greenpeace's campaign targeting the company, comes from Portfolio magazine, which named the IT giant and iPod manufacturer in its Toxic Ten list.

The Conde Nast publication slams the California-based firm for its use of toxic materials in its products. Specifically, it criticises Apple for using polyvinyl chlorides (PVCs) and brominated flame retardants in its popular iPhone and iPod products.

Apple, which declined to comment on the article, had pledged to remove the chemicals from its products by 2008 in the wake of criticism last year from Greenpeace, but came under fire from Portfolio for failing to make the same promise for phthalates, another toxic substance.

The manufacturer is slowly improving its environmental record, said Greenpeace spokesman Rick Hind, who said that it recently moved from four to six out of 10 on the pressure group's quarterly environmental friendliness scorecard for the electronics industry.

But he said that the company was still lagging behind other large computer manufacturers, including Dell, HP and Lenovo, adding that its score also trailed many cellphone manufacturers.

Many phthalates are contained in PVCs, which means that they should be automatically removed when Apple eliminates PVCs from all its products. However, the charity has also found the chemicals in computers that did not use PVC material, Hind explained.

"That's about half of it. The other half is the failure to have a global takeback and recycling programme," he added. "Apple is perceived as a hip, green, cool company but the marketing is greener than the product."

Other companies highlighted as environmentally unfriendly in the Portfolio list included Chevron, Ford Motor, and Boeing.