The threat of a catastrophic loss of life in the Twin Ports has been hanging over our heads - not unlike last week's sooty-black smoke plume - for at least seven years.

Despite so many breathless reports recently, the "news" that the oil refinery in Superior uses hydrogen fluoride during its processing of high-octane gasoline should not have come as any shock. The chemical's use here was first reported in the News Tribune way back in February 2011.

"(The) dangerous chemical ... puts workers and nearby residents at unnecessary risk - even though experts say safer alternatives are available," a collaborative investigation by the Center for Public Integrity, ABC News, and the Wisconsin Center for Investigative Journalism reported at the time, according to the article. "The worst-case scenario: A low-hanging cloud of HF could travel 25 miles, which could envelop Superior and Duluth and put 180,000 people in the Twin Ports area at risk of injury or death."

Despite the front-page story, and despite alarms being sounded by public-interest groups for years before the story, especially after 9/11, about the perilous dangers posed by the chemical and its use, little happened. Little outrage was heard here in the Twin Ports.

Until now. A near tragedy shouldn't have been necessary for attention to be focused on the use of hydrogen fluoride in our community and the worst-case scenario that could result. But after the Husky Energy refinery fire last week burned to within 200 feet of the tank containing hydrogen fluoride, attention can be welcomed - and seized in the name of safety.

The mayors of both Duluth and Superior on Tuesday did what Twin Ports mayors in 2011 didn't: They called on the Superior refinery to stop using hydrogen fluoride.

"I consider last week's explosion at the Husky oil refinery as a clear call to action," Duluth Mayor Emily Larson said in a statement. "We welcome their investment in our economies and the good-paying jobs this work provides. However, choosing the known risks of hydrogen fluoride is not something that is in keeping with the premise of being a good corporate partner."

The mayors urged Husky Energy to use sulfuric acid instead, which is seen as safer.

While the company agreed to examine its chemical use once the investigation into last week's fire is complete, a probe that could last a year, it also seemed to defend the use of hydrogen fluoride. On Wednesday, a day after the mayors' tough talk, Husky Energy released fact sheets, one of which argued that "HF can be handled safely without adverse risks to humans or the environment if used and handled in accordance with applicable industry risk management practices.

"Workers at the refinery safely work with HF every day," the company's document continued. "HF alkylation is a proven, effective, and efficient technology. About one-third of the refineries in the United States use HF to produce gasoline. Husky takes appropriate precautions and follows applicable regulations and best management practices to ensure the safety of our workers and the public. This includes the use of multiple protection levels for the HF tank."

All of that may be true, but defending, or even just explaining, the use of hydrogen fluoride - especially so soon after last week's terrifying explosions, roaring fire, and disruptive evacuations - can be seen as at least curious.

Or maybe not when considering the astronomical cost of converting a refinery for something safer: $50 million to $150 million, the 2011 news story reported, citing industry estimates.

So while the threat of a catastrophic loss of life in the Twin Ports isn't new, and remains frighteningly real, talk of safety and preventing tragedy is - and can be encouraged, even if we should have been talking and considering action for seven or more years now.