NEW ORLEANS (AP) _ Employees at four abortion clinics arrived at work today to find the buildings vandalized with a stinky chemical that one worker said smelled like vomit.

``Some noxious chemical or gas was introduced into the clinics,'' FBI spokesman John Rook confirmed.

The FBI was called in because the use of the chemical, which forced the four New Orleans clinics to close for the day, could be deemed a violation of federal law protecting access to abortions, Rook said.

Rook would give no details. The New Orleans Fire Department said a chemical called butyric acid was believed used in at least two of the clinics.

Butyric acid has been used before in attacks on clinics in many states.

Yellow police tape surrounded the clinics and workers informed arriving patients that the clinics were closed.

The evacuation of the Planned Parenthood clinic forced police to reroute traffic on busy Magazine Street for a couple of hours. By early this afternoon, a private environmental cleanup company had been called in to rid the clinic of the chemical.