Nov. 20, 2001 — After five days of danger, the massive sulfuric acid spill at St. Croix Alumina was contained on Sunday.
Emergency response crews worked around the clock since Wednesday, when a 97,000-gallon tank of highly corrosive sulfuric acid began leaking at St. Croix Alumina. The cause of the leak was determined to be a faulty flange on the tank.
The leak was stopped Sunday morning by transferring the remaining acid into two other tanks on the Alumina grounds. The transfer, however, occurred only after more than approximately 34,000 gallons of 96 percent to 98 percent pure sulfuric acid was released into the ground below the leaking tanks secondary containment area and half into the inner ship channel adjacent to St. Croix Alumina, said Dean Plaskett, commissioner of Planning and Natural Resources.
"Although the release of sulfuric acid from the original acid tank has stopped, an imminent and substantial danger continues to exist at the site due to the possibility of a leak occurring in one of the tanks to which the acid was transferred," Plaskett said, adding that the leak has caused no injuries. "DPNR will make a more thorough assessment of the environmental impacts of the release when the sulfuric acid has been safely contained and/or removed and the site is deemed safe by territorial and federal inspectors."
The transfer to the new tanks was accomplished after crews built an acid-proof pipeline and pump system. Plaskett said concrete secondary containment is present around the tanks now holding the acid. As a further precaution, earthen berms were built using caliche soil, which will help neutralize the acid in the event of additional leaks, he said.
"The acids purity is being monitored to determine the potential corrosivity to assist with anticipated containment concerns," Plaskett said. "The focus of the response is now shifting to both off-island disposal or onsite neutralization."