The Miami-Dade County Fire Department identified the substance in four of the attacks as butyric acid, commonly found in rancid butter and perspiration. Its fumes are not life-threatening but can be nauseating.
In at least two of the cases, the acid was poured through a mail slot.
Abortion-rights groups said the attacks, similar to vandalism at three Orlando and Daytona Beach-area clinics last weekend, signal a resurgence in violence against abortion clinics in Florida, a state with a long history of abortion-related violence.
"We consider this a hate crime," said Anne Figueiras, a spokeswoman for the FBI, which was investigating the attacks. Federal teams were sent to all five locations under a 1994 law banning interference with access to abortion clinics.
The attacks came a day after Gov. Lawton Chiles vetoed a "choose life" license plate sought by abortion opponents. No one took responsibility for the attacks, which were condemned by anti-abortion groups.
"We deplore violence that goes on against these people as much as we deplore the violence that goes on every day inside the clinics," said Matt Ozolnieks, vice president of Florida Right to Life in Orlando. "I think what you have is at least a misguided individual out there. I hope the police catch him before he hurts someone."
Abortion rights leaders said the use of acid was an old anti-abortion tactic.
"Once again we have criminals and terrorists acting lawlessly and threatening the lives and health of women and medical professionals," said Kate Michelman, president of the National Abortion and Reproductive Rights Action League in Washington.
The clinics were evacuated while hazardous-materials teams worked to ventilate the buildings. Only one of the clinics was performing abortions at the time.
Two patients from one clinic were taken to the hospital with breathing difficulties and a woman complaining of itchy skin at another clinic was washed down with water.
The abortion-related violence that had plagued the state in the early 1990s had subsided in recent years. No serious incidents had happened since three people were killed in Pensacola in abortion-related murders in 1993 and 1994.
©1998 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed