That old corporate demon Wal-Mart is preaching renewable energy. DuPont is pioneering corn-based bioplastics. General Electric's NBC Universal unit turned off the lights in its studio smack in the middle of a Sunday Night Football broadcast last season and urged viewers to do the same in their homes. Most major American corporations are trying to board the environmental bandwagon, and practically any C.E.O. can expound on the threat of global climate change and the virtues of sustainable growth. But what does all this corporate green really mean?

Condé Nast Portfolio decided to take a closer look (see our coverage of the "green" trend). Concerned that many corporate environmental efforts may be degenerating into self-serving marketing stunts, we endeavored to separate the admirable (Whole Foods' purchase of enough wind-energy credits to offset 100 percent of its electricity use) from the laughable (the "green" holiday window display at Barneys department store last Christmas that recommended such must-have gifts as "a Prius in a pear tree").

Our team consulted dozens of government agencies, court records, and environmental watchdog groups. We also spoke extensively with representatives from the corporations themselves. We looked at firms in a variety of industries, not just the traditional smokestack polluters. This process, though informed by scientific data, contains a heavy dose of subjective judgment. Consequently, neither our Toxic 10 list of offenders nor our Green 11 roster of good guys should be seen as empirical rankings. These are merely companies that we think could be doing better, given their resources and position in their industries, or those that deserve to be commended. We hope our findings will inspire lively debate and, most of all, some serious thought about what corporations can do to really make a difference for the environment.

FOOD

J.R. Simplot Co.
Headquarters: Boise, Idaho
Revenue: $11.9 billion¹

Last summer, the E.P.A. determined that a Simplot factory was the main source of a potentially deadly amount of phosphorus dumped into the Portneuf River.

Simplot produces more than 3 billion pounds of french fries annually and supplies McDonald's with over half of its potato inventory. But some of the company's nonedible products—including phosphate, phosphorus, and nitrate compounds—have made it infamous among environmentalists. For decades, Simplot has stored the waste by-products from its Pocatello, Idaho, fertilizer factory in an unlined stockpile that has contaminated the surrounding groundwater and polluted the nearby Portneuf River with a mixture of toxins, including arsenic and nitrate. Although Simplot has worked to clean up the site, which is listed as a Superfund site, it has also continued to operate the fertilizer plant.

Not only does Simplot process the fertilizer, it also mines the phosphate ore that makes it, a practice that has contaminated southeastern Idaho with mining waste and selenium, a natural trace element that can be deadly in large quantities. The Centers for Disease Control and Prevention has warned of harmful air pollutants from Simplot's Superfund site. In 2004, the company's silica-sand-mining facility in Overton, Nevada, was fined $500,000 by the Environmental Protection Agency for failing to control its sulfur-dioxide emissions. The facility was required to install $2 million worth of pollution-control equipment as well.

What the company says: Simplot understands that certain groups will be upset by its phosphate mining and is working with the government to clean up its sites.

Note: ¹According to most recent annual data available.

Cargill
Headquarters: Minneapolis
Revenue: $88.3 billion

A Cargill plant in Virginia has been overwhelming wastewater-treatment facilities, causing the dumping of toxic substances into the North Fork Shenandoah River.

Cargill's corn-processing plants have been significant sources of carbon monoxide, volatile organic compounds (which can cause cancer), and smog. The company is now working to comply with a settlement it entered into with the E.P.A. and the Justice Department in 2005 that requires it to spend an estimated $130 million to clean up its plants. Cargill has spent most of the past decade battling lawsuits over the dumping of residue from salt production into a holding pond in a wildlife preserve near San Francisco Bay. Last spring, a U.S. appeals court overturned previous rulings against Cargill on a technicality, saying that the polluted pond isn't covered by the federal Clean Water Act because it doesn't seep into navigable waterways. Last summer, the E.P.A. determined that a former Cargill plant in Grand Island, Nebraska, had contaminated the community's groundwater and said it would take up to 30 years to eliminate the contamination.

What the company says: Cargill says it has consistently tried to act in an environmentally responsible way and that private wastewater-treatment plants are to blame for discharges into Virginia's North Fork Shenandoah River.

CARS

Ford Motor
Headquarters: Dearborn, Michigan
Revenue: $172.5 billion

Ford has contributed waste to 40 Superfund sites.

Ford set out to be a leader in greening the auto industry, becoming the first U.S. carmaker to offer a hybrid S.U.V., with its 2004 Escape. The company also recently announced a more fuel-efficient car engine. But the automaker had the second-worst fleetwide gas-mileage rating in both 2006 and 2007, according to the E.P.A. And in 2006, Ford withdrew its guarantee that it would manufacture a quarter of a million hybrid vehicles annually by 2010, opting instead to explore alternative energy sources. Ford recently created the world's largest living-grass rooftop on its Dearborn plant, but the lawn crowns a factory that produces one of the least fuel-efficient vehicles on the market, the F-150. Ford cleaned up its 500-acre Superfund site in Upper Ringwood, New Jersey, in 1994, but the E.P.A. relisted it in 2006—the only time the agency has relisted a site—when tests found that paint sludge still contaminated the area.

 What the company says: Ford says it takes its environmental responsibilities seriously and is committed to creating a better and more sustainable world, whether by increasing fuel efficiency or working closely with local and state authorities on Superfund site cleanups. 

AEROSPACE

Boeing
Headquarters: Chicago
Revenue: $66.4 billion

Studies show that greenhouse-gas emissions from aircraft could more than triple by 2050.

With more than 800 orders already placed and sales of over $100 billion recorded, Boeing's 787 Dreamliner is the fastest-selling passenger jet in history, and thanks to an innovative carbon-composite construction, the midsize 787 will be lighter and an estimated 20 percent more fuel efficient than comparable airplanes. Boeing says it delivers "exceptional environmental performance." But recently, Britain's Advertising Standards Authority, which has been on the lookout for misleading environmental claims in ads, reprimanded Boeing for overstating the fuel efficiency of another aircraft, its yet-to-launch 747-8 Intercontinental. Despite its efforts to reduce CO₂, the company has been less than transparent about its greenhouse-gas emissions. After initially declining to participate in the Carbon Disclosure Project, an investor-led initiative that gathers information on companies' carbon footprint, Boeing responded the past two years but declined to make the information public. Air pollution aside, Boeing was slapped with $500,000 in water-pollution fines last September for its laboratory near Simi Valley, California. According to the Los Angeles Regional Water Board, which levied the fines, Boeing had exceeded limits on dumping dioxin, lead, and mercury, among other pollutants. The E.P.A. is considering adding the 2,850-acre laboratory to its list of Superfund sites, citing concerns about the local drinking-water supply.

What the company says: Boeing claims that it has substantially reduced emissions and noise pollution in its aircraft, that it has an aggressive plan moving forward, and that it calculated the efficiency of its aircraft using the industry-standard formula.

TECHNOLOGY

Apple
Headquarters: Cupertino, California
Revenue: $24 billion

Significant amounts of phthalate, a toxin thought to cause birth defects, have been found in the iPhone and iPod headphone cords.

Steve Jobs has promised a "greener Apple," setting goals for reducing e-waste (Al Gore is on the board), but the company came under fire last May when it rejected two shareholder proposals that were intended to help. Apple pledged to finish phasing out toxins such as polyvinyl chlorides and brominated flame retardants from its products this year, but the iPhone, unveiled after that promise was made, contained both types of chemical, according to tests by an environmental group, which many major cell-phone makers have eliminated from their handsets. Apple's computer-recycling program also lags behind those of some of its competitors. The company will take back old computers for free, but only if a new Mac is purchased directly from Apple and the old one returned within 90 days. Dell, Apple's main rival, will accept any Dell computer, anytime.

What the company says: Apple says it plans to eliminate PVCs and brominated flame retardants by the end of 2008. It has no comment on the phthalate issue.

UTILITIES

Southern Co.
Headquarters: Atlanta
Revenue: $15.2 billion

Southern operates the top three carbon-dioxide-emitting plants in the U.S.

Southern provides power to more than 4 million customers, but its plants emit a mass of noxious gases across the southern United States. Analyzing E.P.A. data, the Environmental Integrity Project reports that Southern runs six of the 50 dirtiest power plants in the country in terms of sulfur dioxide, carbon dioxide, nitrogen oxide, and mercury released. Its Bowen plant in Georgia, run by subsidiary Georgia Power, is the biggest American sulfur-dioxide polluter. Southern owns the top three carbon-dioxide-emitting plants in the U.S., two of which rank second and third in mercury output as well. And five of its other plants are among the country's top 50 nitrogen-oxide producers.

What the company says: Southern continues to invest billions of dollars to lower its chemical and greenhouse-gas emissions while also seeking out new ways to produce cleaner energy.

American Electric Power
Headquarters: Columbus, Ohio
Revenue: $13.1 billion

American Electric Power is one of the biggest mercury polluters in the U.S.

American Electric Power has been winning praise for cutting back its greenhouse-gas emissions. The Ohio-based utility company plans to implement new technology that stores carbon dioxide underground instead of releasing it into the atmosphere. But the company still releases large amounts of mercury.  Analyzing E.P.A. data, the Environmental Integrity Project ranked five of A.E.P.'s plants among the 50 biggest mercury polluters in the U.S. in 2006. The company's Pirkey, Texas, plant had the worst ratio of power produced (roughly 5 million megawatt hours) to mercury released (over 1,000 pounds). According to the E.P.A.'s toxic-release inventory, A.E.P.'s plant in Winfield, West Virginia, is the 22nd-biggest polluter in the country, releasing more than 20 million pounds of toxins each year, not including carbon dioxide.

What the company says: As a large producer of electricity, A.E.P. would naturally expect to find its plants atop lists for emissions by volume. However, A.E.P. claims that its plants operate in compliance with state and federal environmental regulations and are among the most efficient in the world. The company has reduced mercury emissions by installing new technology.

ENERGY

Massey Energy
Headquarters: Richmond, Virginia
Revenue: $2.3 billion

Massey owns a controversial sludge reservoir that lies less than 400 yards from a West Virginia elementary school.

As one of the largest practitioners of a mining technique known as "mountaintop removal," Massey, the fourth-largest coal company in the U.S., is responsible for leveling peaks across the Appalachians and polluting miles of streams with waste from the blasts. Responding to public criticism, the company launched a radio and TV ad campaign in 2005, along with a website, OurTotalEnvironment.com, saying it works to restore the land it has mined and uses the most environmentally friendly processes available. In January, Massey agreed to pay $20 million, plus take a series of steps to ensure compliance, to settle a suit brought by the E.P.A. for more than 4,000 counts of illegally dumping coal sludge into waterways in West Virginia and Kentucky. The suit claimed Massey has "an extensive history of violating the Clean Water Act."

What the company says: Massey says that the sludge reservoir isn't toxic, that it restores any peaks it levels, and that it does not pollute streams.

Chevron
Headquarters: San Ramon, California
Revenue: $207 billion

Chevron has contributed waste to more than 90 active Superfund sites.

Chevron has spent billions on alternative-fuel technology and research and touted its green credentials when it bought a 20 percent stake in a Galveston, Texas, biodiesel plant. But that partnership fell apart soon after the plant's May 2007 opening when the partners sued, alleging Chevron had failed to give a needed cash infusion. In December, the New York City comptroller filed a shareholder resolution asking Chevron to look into its environmental record around the world. Among the causes for concern: The oil company was fined more than $300 million by the government of Kazakhstan in October for environmental violations. In the U.S., Chevron has faced fines from state and federal regulators over its water and air pollution, including $1.8 million over the past five years for its Richmond, California, refinery.

What the company says: Chevron says it has taken great steps to reduce its energy use and invest in renewable and efficient energy technology. It believes the charges against its environmental record are inaccurate and misleading. It says it has honored its contractual obligations to the Galveston plant. Read Chevron's full response.

ALUMINUM

Alcoa
Headquarters: Pittsburgh
Revenue $30.7 billion

Alcoa's aluminum smelters release 6.1 million pounds of air pollution annually.

Alcoa's corporate environmental push, called Ecoalcoa, has some solid initiatives, such as plans to reduce the company's nitrogen-oxide and mercury emissions, but its power plants are among the dirtiest, on a pollution-per-megawatt basis. Though only a small producer of power compared with Southern or American Electric Power, its plant in Warrick County, Indiana, produces nearly 30 pounds of sulfur dioxide for every megawatt hour it generates, making it the third-least-efficient power plant in the United States.

In 2003, the Department of Justice ordered Alcoa to shut down three of its four Rockdale, Texas, power plants, which at the time the E.P.A. said were the dirtiest in the nation. As part of a consent decree with the Department of Justice and citizens' groups, Alcoa promised to spend $330 million to replace those plants with a new, updated facility. But Alcoa didn't actually close the Rockdale plants until the Justice Department slapped the aluminum company with $9.2 million in penalties in 2006 for nearly 2,000 violations of clean-air standards. The cleaner plant was originally scheduled to begin operation in April 2007. But under a new consent decree, it won't open until 2009, and Alcoa will no longer operate it.

Alcoa unloaded another environmental problem by selling its Three Oaks mining operation late last year.

What the company says: Alcoa says it has been working to improve its environmental record and has no comment on the criticisms raised.

—Research by Ben H. Carmichael, Frank Hentic, Genevieve Smith, and Herman Wong