The burning of large sugar cane fields on Maui has been linked to acute respiratory distress in a new study by health professionals.

The study was the first of its kind to separate symptoms caused by cane burning from vog, said Dr. Lorrin Pang of the Maui Department of Health, a co-author.

Data shows that large cane burns – those exceeding 100 acres – can be harmful to residents’ respiratory health. As a result, Pang recommended that burning be limited to 75 acres or less at a time.

“Everyone knows smoke is bad,” Pang said. “At the higher doses, there is harm.”

Smoke looms over King Kekaulike High School in Pukalani, Maui.
Smoke from a burning sugar cane field rises near King Kekaulike High School in Pukalani, Maui. Courtesy of Maui Tomorrow Foundation

The study, which took four years to complete, was published Wednesday in the Environmental Health journal. The four other co-authors are from the University of Hawaii-Hilo, University of Hawaii-Manoa, the Hawaii Health Information Corp. and the University of California-San Diego.

When Pang started the study several years ago, he said he had the full support of Hawaiian Commercial & Sugar Co., Hawaii’s last remaining sugar plantation. Now the company said it doesn’t support the methodology behind it, Pang said.

HC&S did not respond to Civil Beat’s requests for comment on the study.

For the last century, from March to November, HC&S has torched about 400 acres of sugar cane weekly

Some residents complain cane burning causes health issues and other nuisances such as “Maui snow” – ash that occasionally covers residents’ properties.

According to Maui Health Department rules, HC&S is not allowed to burn on vog days, when volcanic smog – known to cause respiratory distress – from the Kilauea volcano on the Big Island blankets Maui.

This allowed researchers to differentiate between the health effects of vog and cane burning, Pang said.

The data analysis found more reports of respiratory distress on days that HC&S didn’t burn cane, but Pang said this can be explained by the presence of vog.

However, the data also shows that residents who lived downwind of large cane burns had more cases of respiratory distress – for instance, from acute bronchitis and asthma – than those who lived upwind.

Researchers used cane burning data from 2011 and 2012 from the Maui Health Department. They analyzed 55 burn days when 70 to 163 acres were burned close to a residential area.

Health Department cane field maps and Google Earth software were also used to figure out which residents lived upwind or downwind of the cane smoke. The researchers then analyzed data from emergency departments, hospital admissions and four community pharmacies to compare the cases of acute respiratory distress on burn days versus non-burn days.

The study found overall, the “higher proportion of respiratory distress from exposed areas on burn days was not significant.”

But when more than 100 acres were burned, there was a significantly higher number of reports of respiratory distress – 15.3 percent of patients reported respiratory distress downwind of cane fields on a burn day, compared 7.1 percent on a non-burn day.

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