Security chiefs at the Ryder Cup are prepared for a chemical attack by terrorists.
Police at the golf contest will be kitted out with gas masks and chemical weapons suits. Radiation detectors and decontamination units will also be on the course.
Security has been stepped up as it was believed President Bush may drop in on the tournament in Michigan which starts tomorrow.
All golf fans will have airport-style metal detector checks before being let in. Shoes will also be screened for explosives.
No private cars will be allowed within half a mile as spectators are bussed in. It is feared al-Qaeda may launch an attack on the competition between the US and Europe.
Police chief William Dwyer said: "People are coming in from all over the world. We could be a target."
It is the first Ryder Cup in the US since the September 11 atrocities."