The death toll in the months after Hurricane Maria has been raised from 64 to 2,975 by the island's governor. The study found poor people and elderly men had been most at risk when the hurricane struck last September.
The George Washington University Milken Institute School of Public Health (GW SPH) issued its assessment on Tuesday of the excess number of deaths which were due to Hurricane Maria after it hit Puerto Rico.
The figure of 2,975 came from a comparison between predicted mortality under normal circumstances and deaths detailed after the hurricane landed in September 2017 and in the following five months to February 2018.
Carlos Santos-Burgoa, the professor of global health who was the lead investigator of the study said: "We lack a culture of preparedness." Much of the island was left without electricity for months as 240 kilometer-per-hour (150 miles per hour) winds swept across the island, causing an estimated $90 billion (€76 billion) in property damage.
"The inadequate preparedness and personnel training for crisis and emergency risk communication, combined with numerous barriers to accurate, timely information and factors that increased rumor generation, ultimately decreased the perceived transparency and credibility of the Government of Puerto Rico," the report noted.
"Those interviewed said they did not receive information about how to certify deaths during, or in conditions created by, a disaster," according to the report.
Financial instability and a fragile infrastructure made the Caribbean island particularly vulnerable to such weather events, Santos-Burgoa said.
Death toll raised
Puerto Rico Governor Ricardo Rossello immediately announced he was raising the official count of the death toll.
"Even though it is an estimate, we are officially changing, we are putting an official number to the death toll," Rossello said.
"We will take the 2,975 number as the official estimate for the excess deaths as a product of the hurricane."
US presidential response
The study's findings highlight President Donald Trump's response at the time as he defended the US response and criticized San Juan Mayor Carmen Yulin Cruz for her "poor leadership ability" after she had issued an appeal for help.
Trump also remarked about the limited loss of life, compared to what he called "a real catastrophe like Katrina," which had left 1,200 people dead in New Orleans in 2005.
On Tuesday, Yulin Cruz said the study "reinforces the pain inflicted on the people of Puerto Rico."
"These deaths due partly to negligence. For you can kill people with a gun or you can kill them with neglect. The second happened in [Puerto Rico]," she wrote.
Poorer and elderly hit hardest
The report also found that the risk of death was 45 percent higher for people living in "low socioeconomic development municipalities" and that men older than 65 saw a continuous elevated risk of death.
Governor Rossello said he would create a commission to implement recommendations from the report and create a registry of people most vulnerable to a future storm; such as the elderly, bedridden or kidney-dialysis patients.
A previous study by researchers at Harvard University set the death toll from the hurricane at a higher 4,645 but reflected the opinion of the GW SPH study as it noted the numbers "underscore the inattention of the US Government to the frail infrastructure of Puerto Rico."
jm/bw (Reuters, AP)