Workers have neutralized almost 340,000 pounds of hydrofluoric acid at a South Philadelphia oil refinery that went up in flames earlier this year, a city official announced Friday.
The neutralization of the hydrofluoric acid, or HF, was completed this week and represents progress, but there is still a long way to go before officials declare the situation at the Philadelphia Energy Solutions refinery "under control," Philadelphia Fire Commissioner Adam Thiel said.
"That substantially reduces the risk to the community. However, it doesn't eliminate it. There still is HF on the site, albeit in much smaller quantities and in disperse locations," he said.
Even when the situation is eventually declared "under control" -- meaning workers have mitigated most of the risk to the community -- "that doesn't mean it's over," Thiel said. Additional neutralization work, as well as the investigation into the cause of the explosions and subsequent fire, will continue for an indefinite amount of time.
"The remaining work is going to take much longer because of the way the unit is configured," he added.
Hydrofluoric acid is often used by refineries as a catalyst to create high-octane fuel. Tens of thousands of gallons of the solution were released when a series of explosions triggered blazing infernos at the South Philadelphia refinery the morning of June 21, Thiel said.
HF can form a toxic cloud at room temperature that travels low to the ground. If it comes into contact with human tissue, it can cause burns and even cardiac arrest.
HF is currently being kept in vessels near the South Philadelphia refinery. Every day, contractors work to neutralize it by mixing the HF with basic compounds. The process is slow and subject to environmental setbacks, such as lightning and extreme weather, Thiel said.
Though he would not confirm how much hydrofluoric acid remains, Thiel said the amount is "much smaller than the 340,000 pounds that we neutralized and is no longer on the site."