Hydroflouric acid, or HF, is so toxic that a small splash of it on the skin can be fatal. Philadelphia Fire Commissioner Adam Thiel said workers in hazmat suits are combining a strong base with the acid to "neutralize" it.
"The resulting products can be dealt with here on the site. They can go into the permitted and regulated by DEP waste water treatment plant that's operated here on the site and DEP is maintaining very close oversight of that," he said.
Thiel emphasized that safety was the top priority of the operation and said that's one reason it's taken so long to begin it.
"We're tracking and managing and planning for a wide range of things that could happen and the impacts both inside the fence line and potentially to the community. We think that we have been able to reduce the risk to a level that we can manage it," Thiel said.
He added it's hard to predict how long it will take but said it would be at least a few weeks.
"The good news is the quantity of HF on the site is reduced each day that this neutralization process is happening."
The fire department continues to maintain a round-the-clock presence at the site.