* Lawsuit alleges Dow, Sasol spied on Greenpeace
* PR firms Ketchum, Dezenhall also named as defendants
By Ernest Scheyder
NEW YORK, Nov 29 (Reuters) - Environmental activist group Greenpeace sued Dow Chemical (DOW.N) on Monday, accusing the largest U.S. chemical maker and others of spying on it for three years to disrupt its activities.
The lawsuit seeks "compensatory, statutory and punitive damages," though Greenpeace acknowledged it largely wants increased publicity.
The environmental group, known for its unconventional methods to promote its causes, said that Dow and other defendants hired a private security firm to keep tabs on it and sift through its trash.
"This is not about money," said Mark Floegel, a Greenpeace employee who helped collect material for the lawsuit. "What we really want is to drag the activities of these people into the light of day and to send a message to corporations that they can't do this."
Greenpeace also sued the North American arm of South African chemical maker Sasol Limited (SOLJ.J) and public relations firms Dezenhall and Ketchum, owned by Omnicom Group (OMC.N). The suit also names four individual private investigators.
Dow, Sasol and Dezenhall were not immediately available for comment. Ketchum said it would review the suit and comment later.
Greenpeace claims that from 1998 to 2000 the two chemical companies and the public relations firms paid a private security firm to plant undercover agents within focus groups, search for documents in garbage and recycling bins, and hack email networks.
The defendants then used the information to track and better respond to environmental campaigns, Greenpeace said in the lawsuit, filed in U.S. district court in Washington, D.C.
The suit also contends that the security firm, Beckett Brown International, used off-duty police officers in Baltimore and Washington to spy on Greenpeace.
The alleged surveillance only came to light when Beckett Brown folded in 2008 and an investor in the firm came into possession of the company's documents, Greenpeace said.
The Washington-based environmental group is famous for unorthodox methods of attracting attention.
Earlier this month, Greenpeace representatives climbed onboard a PEMEX [PEMX.UL] deepwater oil rig off the Mexican coast and hung a banner reading, "Go Beyond Oil."
"Greenpeace is famous for doing nonviolent, direct action. Sometimes it involves civil disobedience. Sometimes it involves going onto a company's property. But we do that and we let people know that. We don't keep it a secret," Floegel said.
The case is Greenpeace Inc vs The Dow Chemical Co, U.S. District Court for the District of Columbia, 10-cv-02037. (Editing by Steve Orlofsky)