Perhaps Browner's biggest triumph came in 1997, when she convinced Clinton to support a stringent tightening of the Clean Air Act's National Ambient Air Quality Standards regarding permissible levels of the ground-level ozone that makes up smog and the fine airborne particulate matter that makes up soot.
  The decision came after months of public review of the proposed new standards that became the most divisive environmental debate of the decade.
 There was a long and fierce internal discussion within the administration, with opposition from the president's economic advisers echoing strong objections from some industry groups who said the costs of the new standards would far outweigh any benefits and that Browner had exaggerated the degree of certainty behind the EPA's scientific reviews on the matter.
 Over eighty environmental and health groups, who had grown quite frustrated with the administration's preference for minimal-cost incremental actions in the area, pressured Vice President Gore to take a stand on the matter, but he remained silent.
 Browner's adamant defense in favor of the new standards was conducted almost single-handedly, in private meetings, Congressional testimony, and public debate, and had come in the face of a silence from the White House that had put at risk her standing within the administration.
 Some within the administration objected to her unwillingness to modify her stance and even suggested she be fired for insubordination.
 Ultimately, Gore lent behind-the-scenes support in favor of the new regulations, which was a key factor in Clinton's final decision in Browner's favor.
 Overall, The New York Times termed Browner's actions "a remarkable piece of bureaucratic bravura" and Time magazine labelled Browner the "Queen of Clean Air".
 As the decision was announced, one which would affect hundreds of American cities and towns, Browner said: "These new standards will provide new health protections to 125 million Americans, including 35 million children."

The change to the standards had to survive Congressional review, but the support of Republicans from the northeast, especially New York Senator Al D'Amato, helped compensate for Democrats opposed to them.
 The new regulations were challenged in the courts by industry groups as a violation of the U.S. Constitution's nondelegation principle and eventually landed in the U.S. Supreme Court, whose 2001 unanimous ruling in the case now titled Whitman v. American Trucking Associations, Inc. largely upheld Browner's and the EPA's actions.
 Browner and the EPA also took action against air pollution caused by motor vehicles, issuing standards in 1999 that for the first time included light trucks and sport utility vehicles to meet the same emission standards as cars, and that would require the sulfur content of gasoline to be reduced by 90 percent over five years.

During her tenure, Browner also began efforts to deal with global warming, giving the EPA authority to regulate carbon emissions causing climate change, although the EPA under the following George W. Bush administration chose not to use that authority.
 Several other policies of hers were reversed in the Bush administration as well.

During Browner's tenure, there were many reports from African American employees of racism directed at them from a network of "good old boys" who dominated the agency's middle management.
The most known of these reports involved policy specialist Marsha Coleman-Adebayo, who in 1997 filed suit against the agency; in 2000, the court found the EPA guilty of discrimination against Coleman-Adebayo, and awarded her $300,000.
Coleman-Adebayo said that Browner allowed the problems to persist rather than trying to clean them up.
In an October 2000 Congressional hearing on the matter, Browner emphasized that minorities had tripled in number in the agency's senior rank during her time as administrator, but was unable to explain why the culprits in Coleman-Adebayo's case had not been dismissed and in some cases had been promoted.
Congressional dissatisfaction with the situation
Perhaps Browner's biggest triumph came in 1997, when she convinced Clinton to support a stringent tightening of the Clean Air Act's National Ambient Air Quality Standards regarding permissible levels of the ground-level ozone that makes up smog and the fine airborne particulate matter that makes up soot.   The decision came after months of public review of the proposed new standards that became the most divisive environmental debate of the decade.  There was a long and fierce internal discussion within the administration, with opposition from the president's economic advisers echoing strong objections from some industry groups who said the costs of the new standards would far outweigh any benefits and that Browner had exaggerated the degree of certainty behind the EPA's scientific reviews on the matter.  Over eighty environmental and health groups, who had grown quite frustrated with the administration's preference for minimal-cost incremental actions in the area, pressured Vice President Gore to take a stand on the matter, but he remained silent.  Browner's adamant defense in favor of the new standards was conducted almost single-handedly, in private meetings, Congressional testimony, and public debate, and had come in the face of a silence from the White House that had put at risk her standing within the administration.  Some within the administration objected to her unwillingness to modify her stance and even suggested she be fired for insubordination.  Ultimately, Gore lent behind-the-scenes support in favor of the new regulations, which was a key factor in Clinton's final decision in Browner's favor.  Overall, The New York Times termed Browner's actions "a remarkable piece of bureaucratic bravura" and Time magazine labelled Browner the "Queen of Clean Air".  As the decision was announced, one which would affect hundreds of American cities and towns, Browner said: "These new standards will provide new health protections to 125 million Americans, including 35 million children."
The change to the standards had to survive Congressional review, but the support of Republicans from the northeast, especially New York Senator Al D'Amato, helped compensate for Democrats opposed to them.  The new regulations were challenged in the courts by industry groups as a violation of the U.S. Constitution's nondelegation principle and eventually landed in the U.S. Supreme Court, whose 2001 unanimous ruling in the case now titled Whitman v. American Trucking Associations, Inc. largely upheld Browner's and the EPA's actions.  Browner and the EPA also took action against air pollution caused by motor vehicles, issuing standards in 1999 that for the first time included light trucks and sport utility vehicles to meet the same emission standards as cars, and that would require the sulfur content of gasoline to be reduced by 90 percent over five years.
During her tenure, Browner also began efforts to deal with global warming, giving the EPA authority to regulate carbon emissions causing climate change, although the EPA under the following George W. Bush administration chose not to use that authority.  Several other policies of hers were reversed in the Bush administration as well.
During Browner's tenure, there were many reports from African American employees of racism directed at them from a network of "good old boys" who dominated the agency's middle management. The most known of these reports involved policy specialist Marsha Coleman-Adebayo, who in 1997 filed suit against the agency; in 2000, the court found the EPA guilty of discrimination against Coleman-Adebayo, and awarded her $300,000. Coleman-Adebayo said that Browner allowed the problems to persist rather than trying to clean them up. In an October 2000 Congressional hearing on the matter, Browner emphasized that minorities had tripled in number in the agency's senior rank during her time as administrator, but was unable to explain why the culprits in Coleman-Adebayo's case had not been dismissed and in some cases had been promoted. Congressional dissatisfaction with the situation 
Carol Browner