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The Supreme Court Decision To Let Mexican Trucks Roll:
Why It May Leave Two Environmental Laws in the Dust


Tuesday, Jun. 22, 2004

On June 7, the Supreme Court issued its unanimous decision in Department of Transportation v. Public Citizen. Rejecting an environmental challenge from public interest and labor groups, the Court gave the green light for thousands of Mexican trucks to cross the border into the United States.

The Court's decision weakened two pillars of U.S. environmental law. One is the National Environmental Policy Act (NEPA), which requires an Environmental Impact Statement (EIS) for major federal actions significantly affecting the environment. The other is the Clean Air Act, which requires that all federal agencies ensure that their activities will not conflict with state plans for attaining air quality standards.

Both of these laws have the broad purpose of injecting environmental considerations into the agency planning process. The decision in Public Citizen, however, could allow agencies to conduct confined, cursory, and compartmentalized environmental reviews. It also increases the likelihood that federal agencies and the public will lack crucial environmental data about government actions.

News reports indicate that before the Supreme Court agreed to hear the case, the Federal Motor Carrier Safety Administration (FMCSA) had begun to prepare a full EIS for Mexican truck emissions. Now, however, that EIS - which likely would have revealed risks to the environment and public health from these mobile sources of pollution - may never see the light of day.

Adverse Environmental Impacts Widely Acknowledged, But Will Not Be Studied

As a result of the ruling, thirty thousand or more Mexican trucks - which are generally older, more polluting, and less safe than their U.S. counterparts - will be allowed to conduct long haul trucking operations to locations across the United States

Recent government studies estimate that eighty to ninety percent of the Mexican truck fleet was manufactured before 1994. In a preliminary environmental review, FMCSA concluded that their emissions "can be expected to translate into incremental increases in premature deaths" and "an enhanced incidence of respiratory diseases" in the United States. A 2002 U.S. EPA study reported a "persuasive" link between inhalation of diesel exhaust and cancer.

Health and environmental impacts could be particularly severe in cities such as Houston, Phoenix, and Los Angeles, which already have poor air quality. The true extent of the impacts may never be known, however, because the Court ruled that FMCSA was not required to prepare a full EIS, and did not need to consider the impact of the trucks on air quality in these and other cities.

Longstanding Truck Ban Lifted by President Bush, But Congress Sets Conditions

The dispute over Mexican trucks dates back more than two decades. In 1982, the United States banned Mexican trucks from U.S. roads, except for a twenty mile zone near the border.

Then, in 1994, the North American Free Trade Agreement (NAFTA) provided that the moratorium must be lifted. But the Clinton Administration kept the ban in place, citing safety concerns.

In February 2001, a NAFTA arbitration panel ruled that the U.S. could not categorically exclude all Mexican trucks. But it allowed the U.S. to put conditions on the trucks' entry and pursue "legitimate regulatory objectives." President Bush then declared his intention to lift the ban on Mexican trucks.

In December 2001, however, Congress passed Section 350 of the DOT Appropriations Act, which was key legislation in Public Citizen. Section 350 prohibited FMCSA from expending any funds to review applications for cross-border trucking authority until FMCSA issued new, more stringent regulations governing application requirements and safety-monitoring.

In other words, Section 350 made FMCSA an independent gate-keeper for the Mexican trucks. It mandated that even if the President lifted the moratorium, the Mexican trucks would not be permitted to roll until FMCSA set the "rules of the road" under which the safety of the trucks could be regulated and monitored. Congress re-enacted Section 350 in 2002 and 2003.

In March 2002, FMCSA issued its final regulations. However, environmental and labor groups quickly filed suit, charging that FMCSA failed to conduct full environmental reviews under NEPA and the Clean Air Act on the impacts of opening the border.

In January 2003, the U.S. Court of Appeals for the Ninth Circuit ruled in favor of the environmental and labor groups.

By that time, President Bush had lifted the moratorium.

The Court's Primary Holding: Full Environmental Review is Not Required

At first glance, the case seems to be a classic trade versus environment standoff. But the Court barely mentioned NAFTA, and instead decided the case under U.S. statutory and regulatory law, on narrow grounds of causation.

As Justice Thomas framed it in his opinion, the question was this: Whose action caused the environmental effects from Mexican trucks traveling throughout the U.S.? Was it the action of the President, in lifting the moratorium? Or was it the action of the FMCSA, in issuing the final safety regulations for the trucks?

That distinction is important, because Presidential actions are not subject to NEPA or the relevant provisions of the Clean Air Act. But if FMCSA's rule-making were deemed to be the cause of the environmental effects, full-blown reviews under both statutes would likely be required.

Justice Thomas concluded that the effects were caused by the President's action, not FMCSA's. He reasoned that "FMCSA has no ability to countermand the President's lifting of the moratorium, or otherwise categorically to exclude Mexican motor carriers from operating within the United States." As a truck-safety agency with a limited statutory mandate, Justice Thomas wrote, FMSCA "lacks the power to act on whatever information might be contained in the EIS."

In the principal holding of the case, Justice Thomas concluded that "where an agency has no ability to prevent a certain effect due to its limited statutory authority over the relevant actions, the agency cannot be considered a legally relevant 'cause' of the effect."

FMCSA Actually Plays A Key Causal Role

The Court's decision is open to strong criticism, however, because in fact, there is a close causal connection between FMCSA's issuance of safety regulations and the environmental effects of the trucks.

Recall that Section 350 made FMCSA an independent gate-keeper of the trucks. As the agency itself stated, because of Section 350, any Presidential order to lift the moratorium "will have no practical effect" until FMCSA issues appropriate safety regulations. The government's petition for certiorari also conceded that "Section 350 did establish the promulgation of FMCSA's safety rules as a condition precedent to processing applications" for cross-border trucking authority.

It seems clear, then, that both the President's lifting the moratorium and FMCSA's issuance of regulations are causes of the trucks' rolling and thus of the environmental effects from their emissions.

Even if FMCSA could not categorically exclude the Mexican trucks, FMCSA did have substantial discretion in issuing its safety regulations. By adjusting the stringency of its safety standards, FMCSA could affect the number and type of Mexican trucks entering by United States. In so doing, it would plainly affect emissions.

FMCSA would regulate the trucks on safety (not environmental) grounds, in accordance with its mandate. But as the agency itself recognized, different safety standards would have varying consequences for truck emissions. These varying environmental impacts should have been studied in an EIS.

The Court should have acknowledged that the FMCSA - along with the Presidential order lifting the moratorium - was a cause of environmental effects from the Mexican trucks, and therefore that a full environmental review was required under NEPA.

Narrow Interpretation of NEPA May Damage the Statute's Long-term Vitality

The Court's decision in Public Citizen appears to be a significant retrenchment in NEPA law.

Numerous prior NEPA decisions from the Supreme Court and appeals courts have held that an agency must prepare an EIS if its actions were a necessary cause of environmental effects, even if other actors not covered by NEPA also had to take action for the environmental effects to occur. In Robertson v. Methow Valley Citizens Council, for example, the Forest Service's issuance of permit to build a ski area was deemed a major federal action affecting the environment, even though a private developer had to take action, in constructing the ski area, to cause the actual environmental effects.

In addition, NEPA has been traditionally understood to require agencies to consider all relevant environmental impacts of their actions, regardless of the agency's particular statutory mandate. Public Citizen seems to cut back on that requirement.

Consider a few examples: Under the traditional view, it was clear that a Pentagon decision to build a military base, or a HUD decision to permit a new housing development, was subject to full-scale NEPA reviews of land-use, traffic, water resources, endangered species, historic resources, air emissions, and other areas far beyond the jurisdiction of the agencies.

Under prior caselaw, as well, when two or more agencies had permitting authority over a project, NEPA was interpreted to require a review of the entire project - not just the particular part being permitted by each agency.

In contrast, Public Citizen now appears to encourage agencies to either avoid full-scale NEPA review or to put on bureaucratic blinders and review only those environmental effects within their "limited statutory authority," ignoring the whole.

Along with the Freedom of Information Act and the federal open meetings laws, NEPA is a core tool for environmentalists and watchdog groups to monitor our government. As Laura MacCleery, auto safety counsel for Public Citizen put it, NEPA "creates an important informational obligation even in the absence of a remedy."

In Robertson, the Court had noted that NEPA plays an important role in providing relevant environmental data to a larger audience beyond the agency, such as decision makers in other parts of federal and state government and the public at large. Yet in Public Citizen, the Court explicitly denigrated NEPA's role for audiences outside the agency, focusing solely on whether an EIS would serve decision making within the agency - another example of the Court's narrowing of NEPA.

Clean Air Act Claims Also Rejected

Applying essentially the same causation inquiry, the Court ruled that FMCSA need not prepare a Clean Air Act "conformity" analysis to assess whether emissions from Mexican trucks will conflict with existing state plans for attainment of federal air quality standards.

The Clean Air Act claims were in many ways more important to the public interest and labor groups than the NEPA claims. NEPA is in essence an informational statute. But the Clean Air Act imposes a substantive prohibition on federal activities that will lead to violations of air quality standards, increase the frequency of violations, or delay attainment.

The states now face a harsh dilemma. States are obligated by the Clean Air Act to plan to meet federal air quality standards, and to impose increasingly strict control measures on their own industries if the standards are not being met. Yet the states will now be exposed to substantial additional pollution from antiquated Mexican trucks rolling down their highways, and they may be forced to ratchet down emissions limits on existing sources accordingly.

Unfortunately, Public Citizen will mean that as the states face these new mobile sources of pollution, the states and the public will have no official data, or even estimates, about the trucks' likely environmental impacts.

That is both troubling and disappointing, because access to information is the first step in preventing and responding to environmental harm.

Noah Sachs is a Lecturer at Harvard Law School. His e-mail address is

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