The Bush Administration's Environmental Protection Agency is no stranger to controversy, and there is more to come within a week or two. This time it's over one of the most well-known and well-documented toxic substances on the planet: lead.

A court order has required the EPA to release its proposal for a revised airborne standard for lead by May 1. The current standard, established in 1978, is 1.5 micrograms per cubic meter. An EPA staff paper from November recommends a considerable strengthening of the level in the range of 0.2 to 0.5. The staff paper also recommends a measurement time of a monthly average, or at least retaining the current quarterly average, rather switching to an annual average.

Minnesota's major lead emitters can be found in a Natural Resources Defense Council database. According to NRDC data, the largest emitter in Minnesota is the Xcel Energy Sherburne Generating Plant near Becker. The coal-powered plant is the state's largest electricity generator.

EPA brass, staff at odds
Other EPA decisions related to lead are bound to be controversial. The EPA brass is pondering the removal of lead from its criteria list of regulated major air pollutants; the staff paper recommends against that, as do several environmental organizations.

Also, the review process by which these decisions are made is being changed, to broaden participation. Critics, including the EPA's own Clean Air Scientific Advisory Committee, say the new review process will be more political and less scientific. Violations of air-pollution standards can result in criminal or civil penalties. States found in noncompliance can lose federal highway funds.

Lead has been known to be poisonous since ancient times. Exposure can be through breathing it in or ingesting it; infants and youngsters are especially sensitive, as it can affect brain development and the central nervous system.

Amounts of airborne lead in the United States have dropped significantly since the mid-1970s, when the federal phase-out of leaded gasoline began. The EPA estimates that (in 1997 data) more than half of the lead emissions are from metals processing; 13 percent are from fuel combustion.

The EPA has been controversial in recent months for its decisions (or inaction) in cases regarding climate change, ground-level ozone standards, and California's efforts to regulate greenhouse gases from vehicle emissions, among others.

After the lead standard is revised, the EPA will attempt revisions for nitrogen oxides and sulfur dioxides.