HP this week came under "attack" from Greenpeace, which was protesting the continued use of hazardous chemicals in the company's products.
According to a report in the San Jose Mercury, while activists painted the words "Hazardous Products" on the roof of HP's Palo Alto headquarters, the environmental group played phone messages recorded by Star Trek's William Shatner.
Greenpeace organised the protest on Tuesday because it claims HP has failed to remove two toxic substances from its PCs this year, despite a voluntary undertaking to do so.
HP responds that it is using less of the chemicals than previously and its working as fast as it can to find substitutes.
The two chemicals at the centre of the controversy are polyvinyl chloride and brominated flame retardants. They are toxic if released into the environment as e-waste.
HP had pledged to stop using them by the end of this year. However, HP is not alone in still using them: most PC makers are battling to find substitutes for these compounds.