A cloud of toxic acid leaked into the air at a chemical plant in South Baltimore's Fairfield industrial area Monday morning, prompting emergency officials to warn nearby workers and residents to shelter in place for several hours.
The leak of chlorosulfonic acid — a powerful, potentially lethal chemical used to make soap and detergents, among other things — was stopped after about 90 minutes and no injuries were reported.
An undetermined amount of the acid was released through a valve while being unloaded from a tanker just before 11 a.m. at the Solvay Industries plant on Fairfield Road, the Baltimore Fire Department said.
A hazardous materials team from the fire department entered the partially evacuated property and stopped the leak at about 12:30 p.m., but anyone within a one-mile radius was asked to remain inside with the windows closed for another hour until the cloud dissipated. About 60 people work at the plant.
"At 1:43 this afternoon, the fire department gave the all clear, and those who had been sheltered in place were able to go back to normal operations," Fire Department spokesman Chief Roman Clark said.
The acid cloud dissipated in the atmosphere and the fire department deemed the area safe, Clark said.
The cause is under investigation.
The Maryland Department of the Environment has asked Solvay for an incident report related to Monday's leak and also plans to send an inspector to the facility, spokesman Jay Apperson said.
Officials will study any lasting effects from the acid leak to the area, including on first responders and nearby neighborhoods, Solvay spokesman David Klucsik said.
"The investigation's just starting," Klucsik said. "We have to wait until the investigation proceeds."
While it is transported as a liquid, chlorosulfonic acid turns into a gas when it's exposed to air.
"The liquid material is considered hazardous for inhalation and produces a white cloud when it comes into contact with air, which was visible at the site on Fairfield Road," Solvay said in a statement.
As a gas, the acid "is very corrosive to the eyes, the skin and the respiratory tract," according to the Centers for Disease Control and Prevention. Usual symptoms of inhaling it include sore throat, coughing, a burning sensation, shortness of breath and difficulty breathing.
In liquid form, it can severely burn body tissue. It can react "violently" with water and with many combustible substances, according to a National Oceanic and Atmospheric Administration database of hazardous materials.
In addition to being used to make detergents, the acid can be used in manufacturing medicines, sweeteners and pesticides.
Founded in 1863 in Belgium and still headquartered there, Solvay is one of the world's largest chemical companies. Last year, it sold about $13 billion of products used in making everything from planes, cars and medical devices to materials for food and beauty products.
The Baltimore plant has a history of producing chemical ingredients for soaps and detergents, industrial cleaners, agricultural products, latex and clear coat finishes, according to the Environmental Protection Agency.
A company called Alcolac opened the Fairfield facility in 1950 and chemical compounds have been produced there for nearly seven decades. Alcolac is still listed as owner of the 7-acre site at 3430 Fairfield Road in state property records.
It's now part of a Solvay business unit that specializes in chemicals used in cosmetics and other personal care items, as well as plastics and other products. The chemicals it produces help give products such as shampoos, detergents, paints and lubricants distinctive properties such as cleaning, softening, moisturizing, gelling or texturizing.
State environmental regulators have reported no issues with the Fairfield facility for at least the past five years, Apperson said.
The EPA once considered the site contaminated with pollution, but it has not been a "brownfield" site at least since an EPA inspection in 2010.
In the late 1980s, Alcolac pleaded guilty to federal charges that it knowingly violated export laws by shipping an ingredient used to make the chemical weapon mustard gas that ultimately went to Iran.
Thirty years later, the EPA placed the facility under a consent agreement for its use and handling of a toxic gas known as ethylene oxide, prompting two air scrubbers and other technology to be installed, according to the agency. The facility stopped using the gas in 1996, the company said.
French chemical and pharmaceutical company Rhone-Poulenc Inc. acquired Alcolac in 1990, later spinning off a chemical subsidiary, Rhodia SA.
Solvay bought Rhodia for $4.8 billion in 2011, a step into new markets after selling its pharmaceutical operation to Abbott Laboratories in 2009.
Solvay also operates a research and innovation center in Havre de Grace, one of six such facilities in North America.
Baltimore Sun reporter Meredith Cohn contributed to this article.