Greenpeace International on Wednesday criticized some major PC makers for backtracking on commitments to reduce hazardous substances in hardware.

Hewlett-Packard, Dell and Lenovo were among the companies pointed out by Greenpeace that failed to stick to commitments to eliminate hazardous substances like polyvinyl chloride (PVC) plastic and brominated flame retardants (BFRs) from their products. The substances could be potentially damaging to the environment and human health.

The nonprofit reserved praise for companies like Acer, Toshiba and Apple. Apple was lauded for introducing a new line of computers that are "virtually free" of certain hazardous substances like PVC plastic and BFRs.

The details were pointed out in Greenpeace's Guide to Greener Electronics, a guide that ranks IT companies based on their environmental and recycling efforts, as well as the power consumption and chemical content in their products.

Greenpeace criticized HP for delaying an earlier commitment to phase out the contaminants from its products from 2009 to 2011. Lenovo delayed a similar commitment to the end of 2010. The nonprofit also pointed out that Dell completely dropped a timeline to eliminate PVC plastic and BFRs from its products, which was earlier set at the end of 2009.

"There are no excuses for backtracking, and no reason for these companies not to have PCs free of PVC and BFRs," wrote Greenpeace on its Web site.

Greenpeace praised Apple for its new line of products being "virtually" free of PVC and BFRs, including PCs like MacBooks. It also lauded Apple for its efforts to reduce greenhouse gas emissions and recycling efforts. However, Apple was criticized for not providing a timeline on removing chemicals from certain products, like arsenic from display glass.

Acer, on the other hand, stuck to its commitment to eliminate PVC and BFRs in its products by the end of 2009, according to Greenpeace. Toshiba also did well in containing chemicals and hazardous substances in some of its products, including three laptop models.

Dell is trying its best to reduce harmful substances in its products, and is already delivering some products that are PVC- and BFR-free, said Michelle Mosmeyer, a spokeswoman at Dell.

"However, as there are no viable alternatives for many of the components used in our products that include these chemicals, we've adjusted our timetable for eliminating them accordingly," Mosmeyer said.

Greenpeace acknowledged that Dell was stepping up recycling efforts and its commitment to reduce greenhouse gas emissions and harmful chemicals. Dell, for example, has launched the G-Series monitors, its first completely PVC- and BFR-free products.