Tech heavyweights HP and Apple have improved significantly in the latest edition of a report that ranks IT firms based on the environmental friendliness of their electronic products.

Greenpeace’s Guide to Greener Electronics showed HP advancing dramatically in the standings by putting out a PC on the market that is virtually free of PVC (vinyl plastic) and brominated flame retardants (BFRs).

Only the power supply unit and cable of HP’s computer still contain these hazardous substances, the environment group said.

“HP has made the first step in catching up with Apple, which eliminated these materials from its entire product line almost a year ago,” Beau Baconguis, Toxics campaigner at Greenpeace, said in a statement.

“HP’s action now puts pressure squarely on its competitors to put more products on the market that are cleaner and safer,” she added.

Earlier this year, Greenpeace said it staged protests at HP’s headquarters in Palo Alto, California, and at its offices in China and The Netherlands, in response to the delay on the company’s commitment to eliminate the harmful substances from its computing products, by the end of 2009.

With the ProBook 5310m Notebook, however, it appears that HP has now reprioritized its toxic phase-out commitment, Greenpeace noted.

Greenpeace said Apple made public details of its carbon emissions last week only, which should improve its scores in the next edition of the ranking.

“With rising environmental concerns of the global consumer, company transparency on these issues is no longer optional and the next logical step for Apple is to act on reducing its emissions,” the advocacy group said.

Dell and Lenovo each incurred a penalty point for delaying their phase-out commitments indefinitely, the report said.

Acer, on other hand, said it will still achieve its target of eliminating PVC and BFRs in all products by the end of this year. Toshiba, in the meantime, has a timeline to phase out these toxic substances in all its products by the end of March 2010.

Nokia remained at the top of the ranking, with a score of 7.5 out of 10, followed by Samsung with 6.9, Sony Ericsson with 6.5 and Philips — which leaped from 7th to 4th place — with 5.9 points. The other climber is Sony, rising from 12th to 8th place.

LG plummeted from 4th to 11th position, weighed down by a penalty point for backtracking on its timeline to eliminate PVC and BFRs in all its products by end of 2010 — only its mobile phones will be free of these toxic substances as of 2010, while phase-out in TVs and monitors has been delayed until 2012.

At the bottom of the ranking is Fujitsu, which scored of 2.7. China-headquartered Lenovo dropped from 16th to second-last place with a score of 2.5.

“Just two months before crucial climate change talks take place in Copenhagen, it is encouraging to see that Philips, Acer, and Samsung support the levels of cuts required to stem dangerous climate change,” said Baconguis. “However, industry giants like Apple, Nokia, and Microsoft are still failing to show climate leadership.”