A national public advocacy group has called on oil refineries, including five in Louisiana, to stop using hydrofluoric acid, a deadly chemical that puts nearby communities at risk in the event of a leak.

In a report called “Needless Risk” issued Tuesday, the U.S. Public Interest Research Group said the threat of a catastrophic terrorist attack should force chemical plants and refineries to rethink how safe their facilities are. It said current defenses against a leak are inadequate.

“Hiring more guards, building higher fences and placing more lights may all be part of a good security plan, but this does not reduce the threat to the community,” the report said. “Switching chemical processes to something less volatile not only reduces the hazard to the community, but reduces the cost of physical security and the attractiveness of the facility as a target for attack.”

Of the 153 oil refineries in the United States, the report found that 50 use hydrofluoric acid to make an additive that increases the octane in gasoline. When released, the chemical, known in the industry as HF, forms a toxic, ground-hugging cloud that can kill on contact. Even minor exposure can cause skin burns and blindness. Inhaling it can lead to lung damage.

A release in 1987 from a refinery in Texas City, Texas, sent 1,000 people to the hospital and forced 3,000 people from their homes for three days.

With 11 refineries using HF, Texas leads the nation, followed by Louisiana with five — including four in the metropolitan New Orleans area storing nearly 2.5 million pounds of the chemical, according to the Environmental Protection Agency.

The Louisiana facilities are Exxon Mobil’s refinery in Chalmette, Murphy Oil in Meraux, ConocoPhillips refining in Belle Chasse, Marathon Ashland Petroleum in Garyville and Placid Refining in Port Allen near Baton Rouge.

On Sept. 30, the Chalmette plant had an accidental release of a small amount of hydrofluoric acid, but no injuries were reported. Chalmette resident Ken Ford, president of St. Bernard Citizens for Environmental Quality, said storage of the chemical puts residents in danger for miles around.

“The public is not aware of what’s going on,” said Ford, who lives a half-mile from the plant.

An official at the Chalmette facility said there are no plans to move away from HF.

“We’re continuing to look at different types of technology,” said Nora Scheller, the plant’s public affairs manager. “We are constantly evaluating that. The biggest thing for us is ensuring we’re running a safe refinery.”

In the wake of Sept. 11, 2001, the plant has beefed up traditional security, and Scheller said it uses cameras and sophisticated sensors to monitor storage tanks for leaks. If a leak occurs, a system of water hoses has been installed to “knock down” the HF cloud and prevent its migration.

But critics warn that a catastrophic attack could render leak-detection and mitigation equipment useless.

Less toxic alternatives to HF are readily available, and one, known as modified HF, was developed by Mobil Corp. and Phillips Petroleum Inc. An Exxon Mobil refinery in Torrance, Calif., made the switch several years ago at a cost of $3.6 million as part of a court settlement with the city. The Exxon Mobil refinery plant in Baton Rouge uses another less dangerous HF alternative, sulfuric acid.

Federal efforts to curb HF use have gone nowhere. A bill by Sen. Jon Corzine, D-N.J., which would force companies to adopt “inherently safer technology,” was derailed after heavy lobbying by the chemical industry. The Bush administration has pushed instead for a voluntary system of security assessments and upgrades.

Rep. Frank Pallone, D-N.J., sent a letter Oct. 9 to Rep. Billy Tauzin, R-Chackbay, chairman of the House Energy and Commerce Committee, requesting a hearing on a companion bill in the House. With the session winding down, chances of it advancing are slim.