PORTLAND — More than a decade has passed since the April day when 16 churchgoers in the tiny farming community of New Sweden drank poison from their coffee cups.

Rose Tanguay was 300 miles away that day, but she remembers it vividly. She was working at the Northern New England Poison Center in Portland, the sole employee covering the night shift when one of the largest criminal arsenic poisonings in United States history unfolded 11 years ago Sunday.

In those early hours, arsenic was far from health experts’ minds. Food poisoning appeared the most likely culprit, Tanguay learned from her colleague working the prior shift, when the initial calls began to filter in to the poison center.

By around dawn the next morning, Tanguay, then a nursing school student, identified the poison as arsenic. She and the poison center’s director, whom Tanguay awoke from bed with her suspicions, say she was the first to make the startling discovery.

Her quick thinking was critical to the diagnosis and treatment of the poisoning victims, whose conditions were becoming graver with each passing minute.

“I was new, I wasn’t even a nurse yet, and I’ve got this far-fetched, harebrained idea that these people were poisoned with arsenic,” Tanguay said recently, seated in her office at the poison center, where a skull-and-crossbones rug decorates her floor.

Dozens of medical providers, public health officials and others investigated the case, interviewing patients and collecting samples from the Gustaf Adolph Evangelical Lutheran Church before police ever came on the scene. Tanguay and many of those involved credit Maine’s health community for rapidly and efficiently collaborating to respond to the crisis.

Despite intense media coverage of the New Sweden poisoning, including t wo books written about the event, Tanguay’s story has never been told. Even her children knew little of her involvement. Patient privacy rules prevented her from saying much at all. Her only recognition came when her poison center supervisors mentioned her name during a presentation about the case at a meeting of the American Academy of Clinical Toxicology.

“I don’t care who claims the fame,” Tanguay said. “I know what I did in my heart and I know I saved a bunch of lives. Really, that’s all that mattered.”

The sooner arsenic poisoning is identified, the more rapidly patients can receive an antidote to rid the body of it.

The 16 parishioners in New Sweden fell ill after attending church services and a coffee reception. Walter Reid Morrill, 78, died the next morning. The poisoning attracted national media attention as doctors in Caribou and Bangor labored to keep the poison from claiming the lives of the other 15 victims.

About a week later, Daniel “Danny” Bondeson, 53, of Woodland shot himself in the chest and left a note claiming responsibility. Months of investigation followed. The state attorney general’s office announced in 2006 that the case was closed and officials were convinced Bondeson had acted alone, though some people believed otherwise.

Three years later, in 2009, 67-year-old Frances Ruggles died after what her family described as a long and courageous battle with the health effects from the 2003 poisoning.

The case, which occurred not long after 9/11 and the 2001 anthrax scares, reminded state and federal officials of the dangers of a homegrown attack, even in rural Maine, during heightened fears of foreign terrorism in major U.S. cities. It changed how Maine and other states prepare for public health emergencies, even today.

Following the clues

Lois Anderson, 69, tries not to think about the day she was poisoned at church all those years ago.

“As Easter was coming up I said, ‘Oh my goodness, it’s almost 11 years,’” she recalled.

The damaging health effects from the arsenic lingered, likely exacerbating the normal effects of aging, she said. Anderson relied on a walker and struggled with her short-term memory. Some recollections from her children’s younger years just disappeared, and shopping trips required her to list all the stores in order and the items she needed, or she would forget.

“The doctors said that our bodies had aged by 20 years,” she said.

Anderson planned to substitute teach at Sunday school that day, stopping after church services to grab a tuna sandwich and a cup of coffee. She sweetened it with one Equal, possibly masking the bitter taste other parishioners later reported.

“I ended up tipping the urn to get the last cup of coffee,” she said.

She drank half the cup, then threw it in the garbage along with much of the sandwich, which had been made the day before. Anderson had joked it might make her sick.

A state health inspector later spotted a heap of mostly full coffee cups in the trash, the first clue that the brew, not the food, was the source of the poisoning.

Anderson got sick within minutes, sitting on the church stairs so the children couldn’t see her, she said. Many days later, she was the last of the victims to leave Cary Medical Center in Caribou. Some patients were taken to Bangor.

Tanguay, working her shift at the poison center, received a call around 2 a.m. Monday from an Eastern Maine Medical Center physician stumped by a patient’s symptoms, she said. When she learned the patient, like Anderson, had grown violently ill within minutes, she ruled out food poisoning, which takes longer to cause symptoms, Tanguay said. Even detergent, perhaps used to clean the coffee pot, wouldn’t cause such sudden distress, she said. Heavy metals, however, are highly irritating to the stomach and can cause almost immediate vomiting.

“It was just something in my head that said it didn’t make sense,” she said.

Tanguay took every research book off her shelf and pulled up numerous computer sources. She wracked her brain, full of facts and information from studying for both her nursing exam and a certification test for the poison center. She eventually pieced together that whatever was making the patients ill was dependent on the dose, with those who consumed more getting the sickest.

None of the patients had burns in their mouths, eliminating ingestion of a corrosive substance as an explanation.

“This light bulb went on because I’d been studying for my certification exam, and I said, ‘Oh, it’s arsenic,’” she said. “And at that time I’m going, it can’t be, at the same time, because this doesn’t happen.”

A state testing lab later detected 6,300 parts per million of arsenic in the leftover coffee. By comparison, the Environmental Protection Agency allows no more than 0.01 parts per million of arsenic, a naturally occurring substance in soil and bedrock, in public drinking water.

Arsenic can cause a variety of symptoms, some of them long-term, including numbness in the hands and feet, partial paralysis and blindness. It also has been linked to various types of cancer.

Four of the New Sweden victims were maintained on life support for several days at Eastern Maine Medical Center.

Tanguay called the Bangor doctor back and relayed her suspicion. The doctor was incredulous, Tanguay said, as was Dr. Karen Simone, the poison center director, and the center’s medical director after Tanguay roused them from sleep.

“I think we could have stumped 20 toxicologists with that question,” Simone said.

After some convincing, Tanguay’s supervisors came around to her theory and conference-called the two hospitals for updates on the other patients. All had similar symptoms — including low blood pressure, vomiting, abdominal pain and diarrhea — but to varying degrees. The patients weren’t responding to intravenous fluids, used to treat low blood pressure, Tanguay said. Arsenic causes fluid to leak out of the body’s circulation, another sign she was on the right track, she said.

“At the time I didn’t really think criminal activity,” Tanguay said. “I just thought somebody did a big oops.”

Ripples from the New Sweden case

In Augusta, officials with the Maine Center for Disease Control and Prevention, then known as the state Bureau of Health, rushed to identify the poison so doctors could begin treatment. Working with the poison center, the two hospitals, a nurse epidemiologist and others, the state came to suspect heavy metal poisoning during the morning of Monday, April 28, 2003, according to Dora Mills, then the director of the bureau.

Mills, now an administrator at the University of New England, just happened to recall that many potato farmers once used arsenic as a pesticide and herbicide in their fields. Now banned for such applications, arsenic killed off potato vines, making the potatoes easier to pick.

“My grandparents had a potato farm in Ashland, which isn’t far from there,” she said. “I remembered they kept bags of arsenic powder in the back of the barn … Sure enough, that was the source.”

The poisoning touched off one of the most significant public health interventions in Maine’s history. It also prompted a critical shift in the use of federal bioterrorism funds, made available to states in the wake of 9/11.

Just weeks before the incident, the state had ordered chemical antidote stockpiles, many of which ended up saving the lives of most of the New Sweden victims. Before the poisoning, states couldn’t use federal bioterrorism funds to create local stockpiles, Mills said. Instead, the U.S. CDC planned to set up regional caches of emergency supplies that could be delivered anywhere in the country within 24 hours, she said.

Mills wasn’t satisfied.

“If you need an antidote, you need it a few minutes ago,” she said.

Maine tracked down another funding source months before the New Sweden case and collected medical disaster supplies. The lifesaving antidotes had just arrived in Portland, awaiting distribution, when the poisoning struck. State police troopers ferried the antidotes to the Bangor and Caribou hospitals, lights and sirens blazing.

Some patients were so ill that the standard antidote, administered through a painful injection into a muscle, didn’t fully work. A more effective intravenous form was flown in from California. The speedy administration of the first antidote likely saved lives and spared the victims from further internal damage.

Federal authorities, after pressure from Mills and reviewing Maine’s response to the poisoning, freed up the bioterrorism funds and encouraged other states to create their own stockpiles. Maine now has pharmaceuticals stashed at hospitals throughout the state, from antimicrobials to radiation exposure drugs, ready for mobilization.

“You always think it’s not going to happen to you,” Tanguay said. “It did. Heaven forbid it happens again, we have these great stockpiles all over the state now. My hope is we never have to use them.”

The New Sweden patients are still being monitored for long-term health effects from the poisoning, she said.

As for Anderson, she’s feeling better, getting around more easily and enjoying her garden and her three grandchildren. Folks in New Sweden don’t talk much about the events of that April day in 2003, she said.

“We’ve gone on with our lives and put it behind us,” Anderson said.