DURANGO, Colo. (AP) — Monte Miller shovels a load of coal into a bucket and makes the short journey from his storage shed to his home on the edge of Bayfield, joking aloud that his wife likes to keep the temperature at a steady 75 degrees.
"But we don't have any problem doing that with coal," Miller said.
Miller and his wife, Marsha, have been using coal as their main source of fuel since they moved to their home in 2000. Each year, the couple uses about 2 tons of coal to keep their 2,500-square-foot house warm throughout the winter.
"We heat the whole place for less than $200 a season," Miller said. "It would be more than double that if we used natural gas. And if we used wood, we'd need about five cords at $250 a cord. You do the math."
Burning coal to heat homes was once commonplace, but for decades, the practice has not been used on a large scale as people turned to cleaner forms of energy, such as natural gas, electricity and oil.
According to federal statistics, 2.8 million tons of coal were used for residential use in 1975. That number, however, has dropped to less than 300,000 tons in the most recent data available for 2016.
And a World Health Organization study in 2015 found 55 percent of homes used coal/coke for space heating in the 1940s, but that number dropped to 12 percent in 1960 and below 1 percent by the early 1980s.
Durango and La Plata County also have seen a marked decline in the use of coal.
Local historian and Fort Lewis College professor emeritus Duane Smith said when the area was first settled in the late 1880s, coal was the dominant source of heat in the absence of timber and other forms of fuel.
"We were a coal mining town," Smith said. "That's what people don't realize."
All around Durango, a number of small coal mine operations supplied residents with the plentiful, cheap and easy-to-extract fuel source up until the 1920s. Yet use of the fossil fuel did come at a cost.
"I talked to people who lived here at the turn of the century, and they would talk about days when it was really smoggy, with coal dust and smoke blowing around," Smith said. "It was not a good place to live until they got electricity and other forms of heat."
Cleaner forms of fuel came along, but residential use of coal never truly went away. For years, people have traveled 15 miles west of Durango to a rural stretch in western La Plata County to buy coal from the King I and now King II coal mines on County Road 120, also known as Hay Gulch Road.
About 11 years ago, as the mine planned an expansion, the operator - GCC Energy - contracted with La Plata County resident Mike Crawford to sell the coal at a separate location to eliminate conflicts with mine operations. Crawford opened Hay Gulch Coal and is one of the few sellers of coal in the region. The small outpost is just a few miles from the King II mine.
Crawford said business has been steady since he opened.
People are still drawn to using coal because it's cheap, convenient and can easily heat an entire home, Crawford said.
Because the source of Crawford's coal is only a few miles away, his price has remained remarkably stable: In 11 years, Crawford has had to raise the price for a ton of coal only one time - from $90 to $100. Other sources of fuel, such as natural gas, fluctuate with global market prices.
"Most people spend about $200 to $300 to heat their home for the whole winter on coal," Crawford said. "That's a monthly bill for some."
The business serves about 5,000 customers from all over the Four Corners. About 35 to 40 percent of Hay Gulch Coal's customers live in La Plata County. A small percent is scattered throughout Colorado. Some come as far as Naturita, Gunnison and even Colorado Springs. But the majority of people who buy from Hay Gulch Coal are from the Navajo Nation.
Crawford said many of those customers can't afford other forms of energy nor does the Navajo Nation have the infrastructure for gas pipes or electric lines.
"There would be a lot of people in serious trouble if we weren't out here," he said.
Duane "Chili" Yazzie, Shiprock chapter president of the Navajo Nation, said many people on the reservation make the long trek to Hay Gulch Coal because it's their only source of heat. But he is quick to express concern about the health effects from burning coal.
A 2015 study by the World Health Organization linked emissions from wood and coal heating to health problems such as respiratory and cardiovascular mortality and morbidity, with 10,000 attributable deaths in North America.
Coal typically has a higher content of sulfur and nitrogen, and can release potentially toxic and carcinogenic pollutants such as fluorine, arsenic, selenium, mercury and lead that can be trapped in indoor spaces during combustion.
One study found that reductions in the use of coal for heating in the U.S. from 1945 to 1960 decreased winter mortalities by 1 percent and winter infant mortality by 3 percent, saving 2,000 lives, including 310 infants.
"I think only now people are beginning to realize burning coal inside their home is not advisable," Yazzie said. "But people continue to do it."
According to the Environmental Protection Agency, only 25 percent of Navajo households use electricity for heat, even though two coal-fired power plants on Navajo land deliver electricity to major cities like Las Vegas, Phoenix and Los Angeles.
The report says the vast majority of households use coal in indoor stoves to keep warm from below-freezing temperatures on the reservation, which has an average temperature of 19 degrees. That means people burn coal around the clock.
There is danger in using coal to this extent. A 2010 study by Dine College and the U.S. Geological Survey found that more than one quarter of these homes were burning coal in stoves that were not designed for the fuel, were not vented properly or at all, or had visible cracks in the chimneys.
These conditions have caused health disparities on the reservation, the study concluded; Shiprock residents have more than five times the risk of respiratory disease than residents of 76 surrounding areas included in the report.
In its report, the EPA said possible solutions would be to replace old stoves, or in the best case scenario, implement solar technologies. Multiple attempts to reach EPA staff to comment for this story were unsuccessful.
With the use of residential coal at an all-time low across the country, the practice is not generally brought into the national conversation about reducing global fossil fuel emissions.
Coal is considered one of the worst contributors to rising global temperatures, and though it is declining, it is still a major factor in global warming.
But those who support using coal for heating homes say it is safe as long as the right equipment is used. Crawford said he's never had a complaint from a neighbor.
"A lot of the people that want to have a problem with it have a problem with it," he said. "But for people here, it's just been a part of their way of life. They don't worry about it."
Miller, 66, said using coal is a lot easier on him and his wife. It's difficult to keep a wood-burning stove going all night, but a few lumps of coal lasts hours. The coal is also easily accessible.
"You're able to just drive to the pickup and never get out of the truck until you have to pay for it," Miller said. "Thank goodness we have a coal mine south of Hesperus where we can buy the coal fairly cheap and haul it home."
On a day in January hours before an approaching winter storm, trucks were lined up outside Hay Gulch Coal waiting for a load. Crawford says they usually see a rush when there's a sudden turn in the weather.
"You can tell by the thermometer whether it's going to be a busy day," he said. "Sometimes the demand is higher than supply and it's hard to keep up."