In a couple of weeks Hawaii’s only sugar grower begins its 143th harvest season on Maui, the last plantation holdout from bygone days when sugar was king in the islands.

But the venerable Hawaiian Commercial & Sugar Co. likely will do so facing greater scrutiny as the Environmental Protection Agency conducts an investigation and emboldened Maui activists take aim at sugar cane burning following an improbable election victory over the corporate growers of genetically engineered crops.

"People are finally realizing they have the power," said Brad Edwards, a Kihei social worker who has been pressing for greater oversight and restrictions on cane burning.

Under pressure by concerned residents, the state Department of Health is considering holding a community meeting regarding HC&S’ 2015 burn permit, said Nolan Hirai, manager of the Clean Air Branch.

The EPA, meanwhile, is apparently looking into whether the plantation is operating in compliance with federal clean air regulations. The agency sent a seven-page letter to HC&S Nov. 24, asking for documents and records about its biomass energy plant and cane burning operations.

EPA spokesman Dean Higuchi said he couldn’t discuss the matter, but Kerry Drake, an official with the agency’s Air Division, responded in an email to a Maui man complaining of an asthma attack triggered by a cane burning episode in December, saying the EPA is "taking this seriously and we are currently conducting a formal investigation of the situation."

Rick Volner, plantation general manager, responded only that the company is "diligently in the process of responding" to the EPA.

While Hawaii’s sugar plantations have closed one after another over the last couple of decades, HC&S has weathered the good and bad times due in part to the scale offered by its sprawling 36,000-acre plantation that takes up vast portions of Maui’s central valley.

The Alexander & Baldwin Inc. subsidiary has been a significant force in Maui’s economy for generations.

Today, it produces 150,000 to 200,000 tons of raw sugar and more than 60,000 tons of molasses each year. With 800 employees, HC&S remains one of the island’s largest employers with an estimated annual economic benefit of more than $250 million, including payroll, benefits and vendor purchases.

But as Maui grows in population and residential development encroaches on the once-remote cane fields, the company is feeling the heat from its neighbors. Residents, especially those who live downwind of the cane fields, complain of episodes of excessive ground-level smoke and ash and aggravated health problems.

Community concern has run hot and warm over the last few decades. In 1997, a campaign to mount a class-action lawsuit fizzled but not before more than 250 people packed the Kihei Elementary School cafeteria to vent their frustrations about health concerns and about "Maui snow," the black ash that falls on neighborhoods downwind of the fields during the burns.

In 2003, HC&S announced it was making an all-out push to end cane burning by seeking alternative methods of harvesting. In 2010, the company announced it would explore converting the plantation into an energy farm aiming to produce biofuels. In each case, however, the company said it found no economically feasible way to make the transformation.

Rob Parsons, Maui County’s environmental coordinator, said he continues to field more calls about cane burning than any other environmental issue on the island.

In recent years the opposition has turned to new technology to help keep the issue on the front burner. Groups called Stop Cane Burning on Maui and Maui Tomorrow Foundation’s Clean Air for Keiki campaign are pushing on the Internet for more restrictions and discussing the issue regularly on social media.

Additionally, they are promoting an app that community members can use on their smartphones to report incidents of excessive cane smoke, ash and fugitive dust to the state Clean Air Branch, Maui County, EPA and HC&S.

In 2013, there were 1,129 complaints generated by the app, while there were about 1,000 complaints last year, Parsons said.

Parsons said there are more people than ever who live downwind of the plantation, and the problem has been exacerbated by a recent trend of decreasing tradewinds in combination with increasing vog, the volcanic emissions from Hawaii island’s Kilauea.

"We’ve had the perfect storm," said Irene Bowie of the Maui Tomorrow Foundation. "There have been less tradewinds and more vog. It’s made field burning more of an issue."

Last year the Shaka Movement made Maui County history when it became the first citizens group to gather enough signatures to qualify a ballot initiative calling for a moratorium on genetically modified crops. Then, it scored a stunning victory in November when voters approved the measure despite $8 million in spending by agrochemical giants Monsanto and Dow AgroSciences in the most expensive and lopsided campaign in state history.

"Last year’s election was unlike anything I’ve ever seen, with so many people mobilized by one issue," Parsons said, adding that cane burning also has that kind of potential.

Bowie agreed: "The whole GMO movement has energized people to become activists. It’s changed the dynamics."

While the GMO moratorium is tied up in court, the Shaka Movement and other environmental groups may turn their attention to sugar cane burning as the annual HC&S harvesting season begins in March.

Mark Sheehan, a Shaka Movement leader, said he plans to discuss cane burning with the group’s board.

"It’s an issue that is not going away," he said.

But Shaka Movement’s Bruce Douglas, who co-authored the anti-GMO initiative, cautioned that activists need to be careful because the last thing they want is for HC&S’ land to end up in the hands of Monsanto. In a perfect world, he added, the land would be purchased and put in public trust to be converted to organic and regenerative agriculture.

"It could be an issue in 2016. It’s ripe for that," he said.

In the meantime, Edwards and others have been pushing for a public meeting about HC&S’ clean air permit, in part because they don’t think the state is doing enough to safeguard the public health.

"Breathing in smoke is not a nuisance. It is a public health concern. It is a parental concern for those who have kids that are forced to breathe in dirty air," he said.

Edwards, who moved to Maui from Oahu 21⁄2 years ago, said he and others are frustrated and angry because it seems neither state health officials, lawmakers or public school administrators are doing anything about the problem.

"It appears that nobody wants to rock the boat, so thousands of people are forced to continue to breathe in toxic smoke on an almost daily basis from March through September," he said.

Hirai said the Clean Air Branch is doing its best with the resources it has. He said the HC&S burn permit has been tweaked over the years to provide greater oversight and regulation.

Monitoring has increased as well. After operating an air quality monitoring station in Kihei since 1987, another station was installed in Paia two years ago and another one is going in at Kahului, he said.

"It looks like it’s totally unregulated but they really do have a lot to comply with. During a burn there is a lot of reporting and a lot of record-keeping," he said.

The state Clean Air Branch, the local regulatory arm of the EPA, has never found an HC&S violation of state or federal air quality standards due to cane burning.

HC&S has spent millions of dollars trying to stop burning, according to the company, but it hasn’t found a solution that also allows it to remain in business.

"Some people don’t believe us, but that is the truth," Volner, the HC&S plantation manager, wrote in an email. "Having said that, we continuously work hard every day to try to reduce the impact on our neighbors of noise, dust and smoke from our farming operations."

He said the company has worked with state health officials to implement additional precautions and restrictions around schools, churches and other sensitive areas and has worked closely with its weather consultants to improve forecasting in order to minimize effects on neighbors.

"Farming, by its very nature, is dirty and dusty and produces noise, odors and smoke — not unexpected in a rural community, but all considered to be nuisances in an urban environment. We have been farming in the central valley for over 140 years and we hope that residents — new and old — share our desire to keep Maui’s central valley green and in productive agriculture."

Volner said the company is already green-harvesting a "significant" number of acres to avoid burning near homes, businesses and schools.

"Unfortunately, to convert our entire operation to a mechanical harvested no-burn system would require us to shrink our plantation significantly and require costly changes to the factory, irrigation systems and mobile equipment fleet. At this time, the implied reduction in revenues (less sugar to sell) and increase in costs does not pencil out," he said.

As for alternative crops, HC&S has been searching for "many, many years," Volner said.

"Unfortunately, we have yet to find a crop to grow on our 36,000 acres that compares favorably to sugar cane with its ability to grow across many soil types and conditions, withstand drought conditions and stand up to Maui’s strong winds."