SAN JUAN, Puerto Rico (AP) -- Hurricane Maria killed nearly 3,000 people in Puerto Rico in the desperate, sweltering months after the storm - almost double the previous government estimate - with the elderly and impoverished most affected, according to an independent study ordered by the U.S. territory.
The new estimate of 2,975 dead in the six months after Maria devastated the island in September 2017 and knocked out the entire electrical grid was made by researchers with the Milken Institute School of Public Health at George Washington University and released Tuesday.
"We are hopeful that the government will accept this as an official death toll," said Lynn Goldman, dean of the institute. "A lesson from this is that efforts for assistance and recovery need to focus as much as possible on lower-income areas, on people who are older, who are more vulnerable."
The finding is almost twice the government's previous estimate, included in a recent report to Congress, that there were 1,427 more deaths in the three months after the storm than the average for the same period over the previous four years.
The George Washington researchers said the official count from the hurricane that hit on Sept. 20 is low in part because doctors were not trained in how to certify deaths after a disaster.
The number of deaths from September 2017 to February 2018 was up 22 percent from the same period in previous years, Goldman said.
The office of Puerto Rico Gov. Ricardo Rossello did not immediately return a message for comment.
Rep. Nydia Velazquez, a New York Democrat, said the report shows the U.S. government failed the people of Puerto Rico.
"These numbers are only the latest to underscore that the federal response to the hurricanes was disastrously inadequate and, as a result, thousands of our fellow American citizens lost their lives," she said in a statement.
There is no national standard on how to count disaster-related deaths. While the National Hurricane Center reports only direct deaths, such as those caused by flying debris or drowning in the floodwaters, some local governments may include indirect deaths, from such things as heart attacks and house fires.
Researchers with George Washington said they counted deaths over the span of six months - a much longer period than usual - because so many people were without power during that time.
"That caused a number of issues," Goldman said, adding that people were forced to exert themselves physically or were exposed to intense heat without fans or air conditioning. "It's fairly striking that you have so many households without electricity for so long. That's unusual in the U.S. after a disaster."
Puerto Rico's government released data in June showing increases in several illnesses in 2017 that could have been linked to the storm: Cases of sepsis, a serious bloodstream infection usually caused by bacteria, rose from 708 in 2016 to 835 last year. Deaths from diabetes went from 3,151 to 3,250, and deaths from heart illnesses increased from 5,417 to 5,586.
The Rossello administration stopped updating its official death toll of 64 months ago and ordered the independent investigation amid reports that the number was substantially undercounted.
The first phase of the study cost $305,000. In the second phase, the researchers plan to focus on the causes of death.
The researchers found that the risk of death was 45 percent higher for those living in impoverished communities, and that men older than 65 saw a continuous elevated risk of death.
They also reported that physicians and others told them that Puerto Rico's government did not notify them about federal guidelines on how to document deaths related to a major disaster.
"Others expressed reluctance to relate deaths to hurricanes due to concern about the subjectivity of this determination and about liability," the report said.
Researchers said they took into account an 8 percent drop in Puerto Rico's population that occurred in the six months after the storm, when tens of thousands fled because of the damage. They also reviewed mortality data, including deaths by age, sex and municipality of residence, from July 2010 to February 2018.
However, they did not share details of the methodology, saying those will be released if the study is published in a scientific journal.
"We did not cherry-pick, I can promise you," Goldman said. "We used very rigorous methodology."
The study also found that government emergency plans in place when Maria hit were not designed for hurricanes greater than a Category 1. Maria was a Category 4 with 154 mph winds. Damage was estimated at more than $100 billion.
In addition, neither the Department of Public Safety nor the governor's communications office had any written crisis and emergency communication plans in place, researchers said.
They made several recommendations, including that the government train doctors better on filling out death certificates and that it develop a policy for preparing for and responding to major emergencies.
The researchers also said the public health system needs to be strengthened, though Goldman said they don't know yet whether those weaknesses contributed to storm-related deaths.
She added that she worries whether Puerto Rico, which is trying to restructure a portion of its more than $70 billion public debt amid a 12-year recession, can adopt any of the recommendations.
"I don't think they have the resources," she said. "That is a very critical issue."