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Know the West

Oil and gas drilling clouds the West's air

Energy industry’s air pollution increasing


There’s good news and bad news about air quality in the West. The good news is that, by two measurements, it’s improving: Sulfur dioxide emissions from coal-fired power plants have dropped 35 percent since 1998, and total emissions from motor vehicles are declining, due to the adoption of emission-control technology.

But in the past few years, pollution from oil and gas drilling "has emerged as a significant concern," according to Patrick Cummins, co-director of the Western Regional Air Partnership, which aims to reduce air pollution. The group includes the Western Governors’ Association, tribes and state governments.

The Rocky Mountain states have become the energy industry’s favorite target, and that means pollution from tens of thousands of engines on drilling rigs, compressors and water pumps, from New Mexico to Montana. Thousands of storage tanks in gas fields vent chemical and natural gas fumes, and nobody knows how many leaks there are in the thousands of miles of gas pipes. The trucks that service the wells raise dust clouds on huge networks of dirt roads. And waste fluids and gases are often disposed of in open-air fires, called "flares."

In all, environmentalists say, oil and gas operations emit more than 200 hazardous compounds, including nitrogen oxide, a triple threat because it forms haze, ozone and acidic precipitation.

Cummins’ group just completed the first comprehensive inventory of emissions from the West’s oil and gas fields. It found that the industry spewed out 310,000 tons of nitrogen oxide in 2002. That’s about half the amount emitted by power plants, and one-sixth the amount from motor vehicles. But the recent upswing in drilling means that the industry’s air pollution has increased since 2002, Cummins says.

And with thousands of new wells proposed for the Rockies, the problem will only get worse.

Hit or miss

Even trying to monitor the industry’s air quality is a challenge in the West: Most monitoring stations are located in cities, where they can measure the worst air quality, or in the backcountry, where the best air is found. Only a handful are located near oil and gas fields.

So for the most part, the industry’s pollution can only be estimated. Researchers use mathematical computer models so complex that predicting impacts from a gas-field expansion can require a year of calculations. And even then the predictions amount to a best guess.

Air-quality standards are not easy to enforce, either. The Clean Air Act says that the region’s air quality can be only slightly degraded from baselines established more than 15 years ago. But although the act requires the states to regulate the industry’s few major sources, such as gas-processing plants, it doesn’t directly cover the thousands of smaller sources throughout the industry’s fields. The states have regulations on some of the small sources, but they’re hit or miss.

Of the three main energy-producing states — Wyoming, Colorado and New Mexico —Wyoming has the strictest rules on emissions from compressors and pumps. But none of those states regulates the smoke-belching diesel engines that power most drilling rigs.

Wyoming’s biggest natural gas development, the Jonah Field near Pinedale, has become a test case for the amount of pollution that future drilling will cause. Plans call for adding 3,100 wells to the 1,000 already in place. In nearby fields, thousands more wells may be drilled (HCN, 8/8/05: Industry walks a fuzzy line between preservation and extortion). That could result in increased haze in Pinedale for a third of the year, according to the Wyoming Outdoor Council, and affect the views in several wilderness areas and two national parks. Standards set up to protect human health from ozone and particulate matter could also be exceeded in the fields.

Getting a grip on pollution

Faced with that prospect, Wyoming’s Department of Environmental Quality is working with two federal agencies — the Bureau of Land Management, which oversees most of the West’s oil and gas fields, and the Environmental Protection Agency — to limit any increase in pollution from Jonah.

The Wyoming agency not only requires emission controls on many compressors and pumps in the Jonah Field, it also prohibits venting from many tanks. This year, it began requiring companies to get permits for flaring, leading to a decrease in that activity. It has installed three air-quality monitors in the area, and plans to install four more monitors next year. "We’ve just started (the enforcement effort)," says Dan Olson, head of the agency’s air-quality division.

The BLM is considering whether to follow the EPA’s recent recommendation that drilling rigs in the Jonah Field switch to cleaner engines. Some companies are voluntarily reducing emissions in the area, and helping to pay for monitoring. Randy Teeuwen, spokesman for EnCana, one of the leaders, says the company wants to earn "support for responsible natural gas development in the communities where we operate."

Environmentalists are closely tracking the progress of the agencies and companies in the Jonah Field, says Bruce Pendery, a lawyer for the Wyoming Outdoor Council. "It’s going to require a more assertive approach," he says. But if the air pollution problem is tackled responsibly, the Jonah Field could become a model for the rest of the industry.

Elsewhere in the West, environmental groups have raised air-quality issues in lawsuits challenging the BLM’s plans for increased drilling in New Mexico’s San Juan Basin and in the Powder River Basin, an immense field of coalbed methane wells in Wyoming and Montana. Some groups would like entire gas fields to be evaluated as major sources, so the Clean Air Act can be applied more directly. After all, says Dan Randolph of the San Juan Citizens Alliance, a gas field "isn’t a bunch of separate activities; it is one plant in a sense."

The author is HCN’s Northern Rockies editor.