The 10th anniversary of 9/11 means the 10th anniversary of the anthrax attacks – which killed five and infected more than a dozen others, while scaring a wide swatch of the nation — is approaching

A decade on, America is just as vulnerable to a bioterrorist attack of that nature, Tommy Thompson, who was Health and Human Services secretary at the time of the mail attacks, told us on ABC’s “Top Line” today.

“As far as anthrax is concerned, we’re still in the same position we were 10 years ago,” Thompson said. “We’ve got a 50-year old-science vaccine that was discovered by the government, and we haven’t moved to the second generation, which we have to.”

Thompson said the US is vulnerable to other diseases – a weaponized smallpox, mustard gas, tularemia – but it’s anthrax that remains the biggest threat.

“It’s anthrax, front and center, which causes the most problems,” he said. “We need to encourage government to encourage companies to develop that second generation counter-measure in order to protect Americans in our country.”

As for the 2001 attacks, where envelopes including anthrax spores were sent to news organizations and congressional offices, the FBI closed the investigation formally in 2008, after the prime suspect, biochemist Bruce Ivins, committed suicide.

Thompson said he’s “not absolutely certain” no one else was responsible, but he said the FBI case was “pretty complete and pretty compelling.”

Thompson said a final announcement on his political future – he is pondering a run for Senate in Wisconsin – is “coming very quickly.”

His prospective candidacy has already drawn fire from the right. The conservative Club for Growth has already attacked him for growing the size of government as governor, and for supporting President Obama’s health care law in its early stages.

The Club’s ad, Thompson said, was untrue.

“They know that their commercial was a falsehood and based upon lies; it’s been proven that way,” he said. “What is really true is that we didn’t spend, we didn’t tax, we cut taxes — all the taxes including the inheritance and gift taxes and the income taxes. And that’s the record people in Wisconsin know me by.”