Activists from environmental group Greenpeace have targeted Hewlett-Packard, painting a slogan on the company's headquarters accusing the firm of using toxic materials in its products.
Around 13 activists clambered onto HP's Palo Alto premises before using paint rollers to daub the message "Hazardous Products" on the roof, Greenpeace spokesman Daniel Kessler told AFP.
The stunt was designed to draw attention to HP's purported use of toxic chemicals such as PVC plastic and flame retardants, Kessler said.
"The long and short of it is that HP said that by 2007 they would phase out use of these toxi-chemicals; they then backtracked and said it would be 2011," Kessler told AFP. "We used this event to communicate that is unacceptable."
Greenpeace also used "Star Trek" actor William Shatner's voice on a robocall targeting workers at HP to protest the firm's alleged use of the chemicals, Kessler said.
HP said in a statement the company was committed to eliminating use of all brominated flame retardant/PVC from its PC products by the end of 2011.
"The unconstructive antics at HP's headquarters on Wednesday did nothing to advance the goals that all who care about the environment share," the statement said.