Introduction

In an unprecedented measure to combat a deadly kidney disease that is devastating agricultural workers in Central America, the president of Costa Rica announced a national regulation to limit heat stress and dehydration among manual laborers.

The new rule, made public on July 25, represents the first time that a government has sought to curb the epidemic by focusing on heat stress and dehydration. The policy comes as growing body of studies point to chronic dehydration from hard labor in tropical conditions as a leading cause of the disease.

In short, the studies show, laborers who harvest sugarcane and other profitable agricultural exports may literally be working themselves to death.

“All the data we have produced continue to indicate that recurrent heat stress and dehydration is the primary driver,” said Catharina Wesseling, a Costa Rica-based epidemiologist for the Karolinska Institute who has studied the disease for a decade.

For more than three years, the International Consortium of Investigative Journalists has examined how a rare type of chronic kidney disease, CKD, is afflicting agricultural workers along Central America’s Pacific Coast, as well as in Sri Lanka and India. A 2012 study estimated that the ailment has killed more than 20,000 people in Central America alone.

Scientists have long suspected the disease is caused by a combination of factors, from heat stress and dehydration to exposure to toxins such as pesticides. Previous policy responses considered by governments mainly focused on pesticide exposure, including a ban in Sri Lanka on Monsanto’s top-selling weed killer glyphosate that was announced in 2014, placed on hold amid industry pushback and questions about the scientific evidence, and recently reinstated this year.

Costa Rica’s new regulation, which was issued by presidential decree, will require all enterprises that employ laborers in tropical conditions to provide water, rest and shade to those workers at increasing levels depending on how hot it is in work areas. The details of which protections are required at which temperatures will be set in negotiations between the government, unions and representatives of the sugar industry and other agricultural companies, said Dr. Roy Wong, a government epidemiologist in Costa Rica who led the official research into the disease.

The rule marks the culmination of a multi-year study into the causes of CKD and whether it should be classified an occupational disease, which was launched in 2012 shortly after the publication of ICIJ’s “Island of the Widows” investigation.

Over more than three years of research, Wong’s team identified the primary risk factors for the disease as being a peasant laborer and engaging in agricultural work between 10 a.m. and 2 p.m. Agricultural workers who labored between those hours were four times more likely to develop CKD than workers with different jobs within the same endemic region and even other manual laborers who worked at different times of day, Wong said.

“Today we can say that this is an occupational disease,” Wong told ICIJ.

Costa Rica’s reform comes days after another study of workers in neighboring El Salvador, published in the journal Environmental Research, offered insights into how heat stress and dehydration may be causing the illness. The researchers measured the kidney function of sugarcane workers before and after their daily shifts, and found that key indicators of damage such as reduced filtration rate increased over the course of a day’s labor at levels influenced by the climate and by workers’ water intake.

“It’s really showing that there are changes in hydration, people really get dehydrated, and that correlates with temperature and liquid intake,” said Wesseling of the Karolinska Institute, who was one of the authors of the study. “That of course has an effect on the kidney.”

Jason Glaser, the president of La Isla Foundation, an advocacy group that helped fund several of the recent studies on dehydration, advised the Costa Rican government on its response to the epidemic, and has been sharply critical of the sugar industry’s labor practices, praised Costa Rica’s new regulation.

“It is the most clear-cut call that companies must provide interventions for workers in high temperatures via water, rest and shade,” Glaser said. “The fundamental trick is making sure this reaches the people on the ground and that it doesn’t just stay on paper.”