WASHINGTON (CNN) -- A quarter of Blackwater security guards in Iraq use steroids and other "judgment-altering substances," according to a lawsuit filed by the families of several Iraqis killed or wounded in a Baghdad shooting in September.

The suit, filed Monday in Washington, accuses the company of fostering "a culture of lawlessness" among its guards and says the use of excessive force helps the company preserve a key selling point -- the fact that none of its protectees have been killed during the four-year-old war.

The U.S. government has paid the company nearly $1 billion for diplomatic security since the invasion of Iraq, a House committee reported in September.

http://www.cnn.com/2007/US/law/11/27/blackwater.iraq/index.html