Proctor & Gamble Co. has tightened security at its Cincinnati headquarters after a breach that allowed Greenpeace activists to unfurl huge banners from the 12th floor of the company’s corporate offices Tuesday, using zip lines. According to The Associated Press, the activists were criticizing the consumer product company’s use of palm oil from a supplier Greenpeace says is tied to tropical forest destruction in Indonesia.

One activist, dressed in unobtrusive business clothes, claimed to have an appointment, and then let others in through another door. They carried their protest materials, including a tiger costume in “inconspicuous bags.”

P&G spokeswoman Lisa Popyk said, “Our global security team is crackerjack, and they have already taken steps to better secure the area.”

The activists have been arrested on burglary and vandalism charges, and authorities say more than $10,000 in damage was done, mostly to window locks.