Study: Reducing emissions and air pollution from informal brick kilns: Evidence from Bangladesh (DOI: 10.1126/science.adr7394)
Companion study: Productivity gains and work conditions in coercive labor markets: Experimental evidence from the Bangladesh brick sector (DOI: 10.1073/pnas.2528388123)
Related study: Scalable deep learning to identify brick kilns and aid regulatory capacity (DOI: 10.1073/pnas.2018863118)
Related study: Health consequences of small-scale industrial pollution: Evidence from the brick sector in Bangladesh (DOI: 10.1016/j.worlddev.2023.106318)
Relatively simple changes to the way traditional brick kilns operate in Bangladesh can reduce pollution, save fuel and improve the quality of bricks they produce.
But research has found that those productivity gains did not translate into better conditions for the people doing the work. The findings come from a multiyear research effort involving Nina Brooks, assistant professor at the U-M School for Environment and Sustainability and affiliate faculty member of the Center for South Asian Studies.
The research began with a question: Could an industry essential to Bangladesh's rapid urban growth, but also a major source of air pollution, become cleaner without requiring kiln owners to make expensive investments in new technology?
The answer was encouraging. But it led to a harder question: If cleaner production also makes businesses more productive and profitable, do workers share in those gains? In the short term, the researchers found, they did not.
Bangladesh is the world's fourth-largest brick producer. Approximately 8,000 traditional kilns supply more than 90% of the country's domestic brick consumption. Brickmaking is also associated with substantial carbon emissions and fine particulate matter, or PM2.5, which contributes to a global public health crisis. Ambient air pollution is responsible for 4.9 million premature deaths globally, but 32% of those deaths occur in South Asia.
For Brooks, the research is the culmination of about eight years of work that began during her doctoral studies. Along with her collaborators, she first worked to understand the industry itself, mapping kilns using satellite imagery and machine learning, examining regulation and studying health effects on communities living downwind. That work also revealed the limitations of regulating where brick kilns can be established alone.
"Bangladesh is one of the world's most densely populated countries," Brooks said. "It is not feasible to move brick kilns away from all schools, health facilities and urban centers that may be harmed by the pollution."
The researchers began looking instead at whether existing kilns could operate more efficiently.
Small changes, measurable gains
Working with kiln owners, managers and workers, the team introduced a set of relatively modest operational changes. These included feeding coal into the kiln more continuously and changing how bricks were stacked so air could circulate more efficiently. Other measures reduced heat loss. None required owners to replace their kilns or purchase major new equipment.
After testing the approach in a small pilot, the researchers expanded it across hundreds of kilns in Bangladesh. The results, published in Science, showed that providing training and technical support on the practices reduced energy use and emissions while lowering fuel costs and increasing the production of higher-quality bricks. Across kilns assigned to the intervention, energy use fell about 10.5%. Carbon dioxide emissions declined by an estimated 171 metric tons per kiln over a firing season, while PM2.5 emissions fell by about 0.45 metric tons.
The effects were greater among kilns that adopted the practices because of the intervention: Energy use declined about 23%, while carbon dioxide and PM2.5 emissions fell by roughly 20%. The economic benefits were important, too. Kiln owners spent less on fuel and produced a greater share of higher-quality bricks.
When researchers returned the following firing season, adoption had not dissipated; in fact, it had increased.
"Because the changes are economically beneficial for owners, they had a strong incentive to continue following them," Brooks said.
For an industry in which expensive technological upgrades can be difficult to finance and environmental regulations difficult to enforce, the results suggested another path: make existing production cleaner while giving owners a financial reason to maintain the changes.
But embedded within the research was another question: Who benefits when productivity rises?
Brickmaking in Bangladesh depends on a large, mostly informal workforce. Labor arrangements can involve debt, advance payments, long hours, limited worker mobility and hazardous conditions. The researchers wanted to know whether making kilns more productive would also improve the lives of workers. Their companion study, published in the Proceedings of the National Academy of Sciences, examined 246 kilns in Bangladesh's Khulna Division and included private interviews with 1,442 workers.
The study found widespread evidence of poor and coercive working conditions. Seventy percent of workers reported lacking personal protective equipment, while 71% said they did not have a formal labor contract. Forty-two percent reported limited freedom of movement or communication.
Moreover, at nearly half of the kilns studied, at least 1 in 6 workers met the U.S. Department of State's definitions of labor trafficking. Across all kilns in the study, the researchers found a trafficking rate of roughly 20%. Adult workers also reported child labor at more than 70% of the kilns in the study, with most reported cases involving children ages 14 to 17.
Against that backdrop, the researchers examined whether the productivity intervention changed working conditions. It clearly changed the economics of production. Fuel costs fell by 9.6%, while brick quality increased by 8.1%. But researchers found no corresponding improvement in labor trafficking, child labor, wages, health or working conditions even though changes during the study period were possible.
The result challenges a familiar economic assumption-that when businesses become more productive, some of those gains will eventually reach workers through higher wages or better conditions. In labor markets shaped by coercion and limited worker bargaining power, the researchers found that this process cannot be assumed.
For Brooks, the findings from the two studies are therefore connected. The first demonstrated that relatively modest operational changes could make kilns cleaner and more productive. The second showed the limits of what productivity alone could accomplish for workers, at least in the short-term.
"In many countries, not just Bangladesh, labor laws are hard to enforce, particularly in informal sectors. So, it's critical to find other ways to protect workers from exploitation," said Grant Miller, professor of medicine at Stanford University. "Our study shows that we cannot rely on productivity gains alone to do that, at least not in the short run. Finding approaches that work beyond regulation is a central goal of our ongoing research."
Why change can be difficult-even when it pays
The researchers have continued expanding their work, including into districts around Dhaka. There they encountered another puzzle. Adoption of the cleaner production practices was considerably lower than it had been in Khulna. Yet among kilns that did adopt them, Brooks said, the effects on fuel use and emissions remained comparable.
"So, we're seeing greater hesitation," she said. "But once they adopt, we see the same benefits."
Why would owners resist a change that can save them money? Sameer Maithel, the lead technical expert on the research team, said there is no single explanation and added that this research was ongoing.
Kilns often operate on narrow margins. Owners may be reluctant to alter practices that already work, even when a different approach could make them more profitable. They also face fluctuating coal prices, uncertainty about demand for bricks, and an unpredictable regulatory environment. Those pressures can make businesses more cautious rather than more willing to experiment.
Geography and local operating conditions matter as well. Differences in kiln size, land and production practices can make the same intervention relatively straightforward in one place and more difficult in another.
"Informal brick production in South Asia faces a lot of uncertainty: weather, energy prices, market demand and regulation all shift unpredictably. Many kiln owners also have limited technical and managerial support, and conditions vary from region to region," Maithel said. "All of this makes scaling up slow and complex, and it takes sustained, dedicated effort."
The experience underscores a broader challenge for environmental and development policy: Proving that a solution works is different from understanding whether it can work at scale.
Turning directly to workers
The finding that productivity gains did not improve working conditions has pushed the research in another direction. Brooks and her collaborators are now testing interventions aimed more directly at workers' needs.
During the most recent brickmaking season, the team returned to kilns in Khulna with measures developed through piloting and conversations with workers. They recommended owners provide protective equipment such as masks for workers crushing coal, goggles and protective footwear for fire workers, and head protection for people carrying bricks, as well as sanitation and cooking facilities, shaded rest areas, access to clean water, heat-stress awareness and information about child labor.
Researchers had expected some resistance from kiln owners, but found many were open to making improvements.
"None of the owners I interviewed objected to improving conditions for workers, though some disagreed with specific components. They saw the cost as negligible compared to what they spend running a kiln. As they put it, if workers do better work because of it, it's worth doing," said Mohammad Saeed Munim, research officer at the Health Systems and Population Studies Division of the International Centre for Diarrhoeal Disease Research in Bangladesh.
For Brooks, the progression of the research has been important. The work began by documenting the scale and environmental consequences of brickmaking. It moved toward testing a practical solution, then toward understanding why adoption differs from place to place and whether economic gains extend to workers. Increasingly, it is asking what must be done when they do not.
