Standing ankle deep in black oil in a green field in Nigeria, Donna Vorhees was startled not by the pollutant inching up her boots, but by the two barefoot women inching past her.

“They were harvesting cassava root even though they were surrounded by oil puddles,” says Vorhees, a Boston-based environmental scientist who spent part of 2011 studying the effects of poorly regulated oil drilling on Ogoniland, Nigeria. “Life here continued as if the drilling had never happened. But in an industrialized country, the area would have been evacuated and there would be no one left to work the fields.”

Vorhees’ experience illustrates the challenges that health advocates face as they work to protect women and families in the developing world from problems related to pollution. These ailments are more common in low-income countries where environmental protections are more lax.

Even so, women’s advocates say that in the past five years, developing countries have made stronger efforts to literally clean up their act. International agencies are also stepping in, as the United Nations did by funding Vorhees’ study, which recommended “emergency action” to help some Nigerian families who were drinking oil-slicked water contaminated with 900 times the accepted level of the carcinogen benzene.

Health experts say that women in the developing world (like women everywhere) have a special set of vulnerabilities to environmental contaminants because their bodies are more sensitive to pollutants that can cause allergies, immune disorders and reproductive and neurological problems triggered by exposure to some synthetic chemicals.

“Research shows that environmental factors are responsible for 23 percent of our overall global disease burden,” says Maria Neira, director of Public Health and Environment for the World Health Organization (WHO), in Geneva. She estimates that addressing this pollution will prevent the deaths of 6 million women per year.

A recent Lancet study found that globally, two-thirds of the 2.6 million annual deaths from air pollution stem from indoor contamination or people inhaling carbon monoxide and fine particles from open fires and wood-burning stoves.

“Since homes in the developing world are often poorly ventilated, stay-at-home mothers and their children are at especially high risk for lung disease and other problems related to this cause,” says Sumi Mehta, director of programs for the Global Alliance for Clean Cookstoves, which is based in Washington, D.C., and promotes biogas, smoke hoods and other abatement measures in India, Bangladesh, China and Africa.

Women are also under increased threat from the 100,000 synthetic substances used in industrial production across the globe. “The female hormonal system is especially sensitive to toxic chemicals in the environment,” says Theo Colborn, a research scientist and founder of the Endocrine Disruption Exchange in Paonia, Colo.

Some of these chemicals are “endocrine disruptors,” substances that interfere with hormone signaling, such as the pesticide atrazine, used more heavily in developing countries than in developed ones. Others are “persistent organic pollutants,” or POPs, organic compounds that resist breakdown and include polycyclic aromatic hydrocarbons, found in the auto exhaust that pollutes cities in developing countries.

When women come into contact with these substances in polluted soil, air and water, toxic chemicals can pass through their skin, nostrils or mucus membranes and into their bloodstreams, their body fat and the umbilical cords that nourish their unborn children.

An estimated 19 percent of cancer, a leading cause of female fatality worldwide, and on the rise in developing countries, can be attributed to environmental causes, reports WHO.

“We’re seeing a global increase in breast cancer, now the most common cancer in women,” says Kathryn Rodgers, a research assistant at the Silent Spring Institute, in Massachusetts. “The biggest jumps are in the Middle East, central Latin America and Asia.”

Authorities say that compared to women in the industrialized world, those in developing countries face a greater risk of health problems that can be attributed to the linked issues of more pollution and less regulation.

“Here, there may be few or no public-education campaigns, and the general population may be unaware of pollution’s threats,” says Joseph DiGangi, a senior science advisor for the International Persistent Organic Pollutants Elimination Network in Gothenburg, Sweden. “Developing countries often have financial limitations, a lack of suitable regulatory policies and ineffective enforcement.”

The WHO’s Neira says the problem boils down to numbers: There’s “less legislation designed to protect human health, fewer citizens protesting against pollution and fewer scientists working to detect problems.”

Even where protocols are in place, says DiGangi, “coordination between ministries of environment and health often needs to be radically improved.”

A lack of data may thwart research efforts. Vorhees notes that in her oil study, researchers didn’t have census records to peg how many people were in each community they studied. Nor did they have comprehensive medical records to show how exposure to oil changed people’s health status over time.

DiGangi adds that many developing nations affected by mercury pollution neglect to measure mercury levels in fish. Mercury, spewed by coal-fired power plants, gets into rivers and then into fish, putting unborn children at high risk of neurological problems if their mothers eat contaminated fish.

Worker safety standards may be shoddy or nonexistent. “In the Ivory Coast, for instance, women workers are recycling car batteries with their bare hands,” says Neira. “This exposes them the neurotoxin lead without the protections they need to stay safe.”

Despite these challenges, developing countries–often at the urging of proactive nongovernmental organizations–are working to reform their policies with help from the U.N. and WHO.

“Governments are learning that if you reduce one source of pollution, you can address a whole slew of health markers and get more bang for your buck,” says Global Alliance for Clean Cookstoves’ Mehta. “By reducing indoor air pollution, for instance, you can help address cataracts, lung disease and heart disease among women; low birth weight and pneumonia among children; and the incidence of cancer and burns among everyone.”

As activists celebrate recent victories for women’s environment-related health, they note their campaign is winning some unexpected converts.

In February 2013, China acknowledged for the first time that pollution within its borders had created “cancer villages,” places where contaminated water and soil have contributed to an 80 percent spike in the country’s cancer rate since 1970 (including higher-than-ever-rates of breast cancer). China pledged to track its use of 58 toxic chemicals and stop industrial production of some known carcinogens.