Forest fires that have ravaged Indonesia since July have blanketed the region in a thick, toxic smoke cloud that has sickened people and endangered wildlife, amid accusations from neighboring Malaysia that Indonesia’s government is not doing enough to control the man-made wildfires.

The blazes, a persistent problem in the summer season, have been largely sparked by farmers who set land on fire to make room for new crops. The arid conditions following the dry and hot summer have made this year’s infernos particularly devastating. The fires have destroyed more than 800,000 acres of land, an area larger than the state of Rhode Island.

Indonesian President Joko Widodo, who this week visited one of the now-barren forest sites, said Tuesday he’d sent 5,600 more personnel to assist in controlling the fires, along with 52 aircraft to dump water on the affected areas.

Police have arrested 185 people accused of starting the fires, the Associated Press reported. Under an environmental protection law that forbids the setting of fires to clear land, they could face up to 10 years in prison.

In Borneo, Indonesia, the fires have also put the native endangered orangutan population in danger. The Borneo Orangutan Survival foundation said, amid a thick and smoky haze, the organization was working to protect the 355 apes in its care, some of which have developed respiratory infections.

The smog could have lasting effects on civilians in neighboring countries. Malaysia shut down hundreds of schools in response to the pollution. Last week the country distributed 500,000 face masks as a thick smog hung in the air.

Such interruptions to Malaysia’s environment have been costly in the past.

A report published by the National University of Malaysia says the country lost $375 million in health care costs and loss of income in 2013, when smoke from Indonesian fires enveloped Malaysia and Singapore.

The Malaysian government said earlier this month it would call on Indonesia to take “immediate action” in extinguishing the fires.

The disasters in Indonesia are only the latest in a year of ruinous forest fires around the world. In Brazil, similar land-clearing methods ignited blazes that have devastated the precious ecosystem of the Amazon Rainforest. And in Australia, fires continue to eat through dry brush in Queensland and New South Wales.

Environmental activists warned that the global demand for Indonesian crops has pushed farmers to fan these destructive flames. Indonesia is the world’s largest producer of palm oil, a product used in everything from peanut butter to shampoo. To continue harvesting this crop, farmers have steadily burned down trees, particularly in the tropical forests of Borneo, to make room for more harvesting.

The practice has climate change watchers concerned. As the New York Times reported in 2018, “NASA researchers say the accelerated destruction of Borneo’s forests contributed to the largest single-year global increase in carbon emissions in two millenniums, an explosion that transformed Indonesia into the world’s fourth-largest source of such emissions.”

Correction: An earlier version of this story incorrectly referred to orangutans as monkeys. They are great apes.