The chemical in butter flavoring for popcorn and other foods that has sickened hundreds of workers, killed a handful and destroyed the lungs of at least three microwave popcorn addicts may be back.

In fact, it appears it never went away, despite promises from the food industry.

So what is the Obama Administration going to do about it? Nothing meaningful, at least for another year, it said this week, stunning unions, members of Congress, public health activists and physicians who have pleaded for government action to protect workers and consumers from the butter flavoring.

Two years ago this month, the nation’s leading popcorn purveyors proclaimed that they’d done away with the chemical culprit diacetyl, believed to be the harmful element in the food flavoring.

But now, government health investigators are reporting that the “new, safer, butter substitutes” are, in some cases, at least as toxic as what they replaced.

Even the top lawyer for the flavoring industry said his organization has told anyone that would listen that diacetyl substitutes are actually just another form of diacetyl.

“We’ve been very clear to flavor manufacturers, food companies and regulators that these so-called substitutes are diacetyl,” said John Hallagan, General Counsel for the Flavors and Extracts Manufacturers Association.

Hallagan told me this week that his trade association discouraged food manufacturers from using these materials and calling their products “diacetyl-free.” But he quickly admitted that his group has no legal authority to prohibit their use.

That’s up to the food manufacturers.”

But those companies refused to discuss the source of the butter flavoring in their products. But their food scientists and flavorists openly debate it at professional meetings as they sought their peer’s opinions on the value of starter distillates and trimers they were using to achieve the rich butter flavors that consumers love so much.

But federal health investigators, many of whom had chased the dangerous additive for years, had concluded that these butter surrogates may be unsafe.

“The inclusion of these alternative substances neither eliminate diacetyl nor assure safety for workers,’’

physicians from the National Institute of Occupational Safety and Health – Drs. Kathleen Kreiss and Nancy Sahakian – wrote earlier this year. Their agency has led the way in chasing which flavoring agents were sickening factory workers.

On the same trail was Dr. Daniel Morgan, with the Respiratory Toxicity Group at the National Institute of Environmental Health Sciences.   On Monday he told me he had found the same danger in one of the principle components of the butter substitute – a concoction called 2,3-pentanedione.

“It caused the same injuries in test animals as diacetyl and our preliminary data indicates the toxicity is close to identical,” Morgan said.

“We don’t really know what industry is using as a substitute in these ‘diacetyl-free’ items. But, if 2,3-pentanedione was being used, it’s being done without toxicity data.”

The disease from exposure to diacetyl – bronchiolitis obliterans – is debilitating and potentially fatal. It irreversibly destroys the small airways in the lung. The only hope for many is a hard-to-get single or double lung transplant.

It was almost ten years ago, the holiday season, that Dr. Allen Parmet, a really sharp occupational medicine doc, used his experience treating victims of a rocket fuel accident to figured out that workers at a Missouri microwave popcorn plant were having their lungs destroyed by some chemical used at the facility.

A team from NIOSH quickly pointed to diacetyl as the likely villain.

Over the years, unions, congress, scores of physicians and scientists and occupational health experts called on OSHA to take action.

In June 2006, Rep. Hilda Solis, a Democrat who represented the Los Angeles district where two stricken flavoring plant workers lived, reacted to media reports on their illness and demanded that that OSHA do more to protect workers.

“”These illnesses and deaths are preventable,” Solis said at the time. “Further inaction is inexcusable.”

Public health advocates told themselves that when Democrats took over the health and safety agencies the Bush regulations-are-bad-era would vaporize. One measurement  was going to be how quickly the Obama team addressed something diacetyl.

Well, this week the new Labor Secretary, who now happens to be Hilda Solis, addressed it.

She released her plans for worker health and safety, mentioning several specific hazards, including diacetyl.

But instead of expediting carefully crafted rules for diacetyl and worker safety, she ordered another year of bureaucratic review of diacetyl’s health effects.

You’ve got to wonder what really happened to Solis’ great concern for workers exposed to diacetyl.

For a longer version of this story, check out what I wrote on AOL News – Sphere.com.