Toxic Threat: Weakened EPA Rules Could Allow Coal Plant Waste into Iowa Rivers

Introduction

A proposed regulatory rollback by the Environmental Protection Agency (EPA) could once again permit coal-burning power plants to discharge hazardous wastewater containing heavy metals like arsenic, mercury, selenium, and lead directly into U.S. waterways. This move threatens to reverse protections established under the Clean Water Act, with significant implications for Iowa's rivers and lakes. The controversy centers on coal ash wastewater—a byproduct stored in landfills and ponds that has long plagued communities near power plants, including those in Sioux City and other parts of the state.

What Is Coal Ash Wastewater?

Coal ash is the residue left after burning coal for electricity. It contains a cocktail of toxic elements—arsenic, lead, mercury, selenium, cadmium, and chromium—that can leach into groundwater and surface water when mixed with water in storage facilities. Power plants often store this sludge in unlined ponds or landfills, where rain and runoff create wastewater that must be treated before discharge. The EPA's 2015 Effluent Limitations Guidelines and Standards for the Steam Electric Power Generating Category set strict limits on how much of these pollutants could be released into rivers, lakes, and streams. The current proposal seeks to weaken those limits, allowing more contaminants to enter waterways without adequate treatment.

The Proposed EPA Rollback

In 2024, the EPA announced plans to revise the 2015 rule, effectively permitting coal plants to use older, less effective treatment technologies for coal ash wastewater. Critics argue this will lead to higher concentrations of toxic metals in effluent, increasing the risk to aquatic life and human health. The agency claims the changes reduce compliance costs for utilities without significantly harming the environment, but environmental groups and state regulators contend the scientific evidence shows otherwise.

Key Changes from the 2015 Rule

• Relaxed limits on selenium and mercury: Plants would be allowed to discharge more of these neurotoxins, which accumulate in fish and can cause developmental problems in humans.
• Extended compliance deadlines: Power stations would have more time to install advanced treatment systems, prolonging pollution periods.
• Exemptions for small and “legacy” facilities: Older plants that are still operating or have closed would face fewer requirements, despite ongoing contamination risks from ash ponds.

These changes directly affect how much toxic waste ends up in nearby waterways, making the issue especially pressing for states like Iowa that rely on coal for electricity generation.

Iowa's Vulnerable Waterways

Iowa has a number of coal-fired power plants, including the MidAmerican Energy plant in Sioux City and others along the Mississippi, Missouri, and Des Moines Rivers. These facilities have historically stored coal ash in ponds that have leaked or overflowed during heavy rains. The proposed rule rollback would allow them to continue discharging wastewater with higher pollutant loads into these rivers—rivers that supply drinking water, support agriculture, and provide recreation for millions of Iowans.

For example, selenium is particularly problematic in Iowa because it bioaccumulates in fish, leading to deformities and reproductive failure. Arsenic and lead can contaminate groundwater aquifers that feed private wells and public water systems. If the EPA finalizes the rollback, communities downstream from coal plants may face increased monitoring costs and health risks.

Health and Environmental Risks

The pollutants found in coal ash wastewater pose serious threats:

1. Arsenic: A known carcinogen linked to skin, lung, and bladder cancer. Even low levels in drinking water can cause long-term damage.
2. Mercury: A neurotoxin that impairs brain development in fetuses and children. It accumulates in fish, making consumption unsafe.
3. Selenium: Causes reproductive failure and deformities in fish and waterfowl. High concentrations can decimate aquatic ecosystems.
4. Lead: Damages the nervous system, kidneys, and cardiovascular system, especially in young children.

Beyond direct toxicity, the nutrients in coal ash can also contribute to algal blooms and oxygen depletion, further degrading water quality. The 2015 rule was designed to prevent these outcomes by mandating treatment technologies like chemical precipitation and biological treatment. Rolling it back could return water quality to levels seen before the rule took effect, when many plants released untreated or poorly treated wastewater.

Conclusion: What's at Stake

The EPA's decision will shape the health of Iowa's waterways for decades. If the rollback is finalized, the burden will shift to states, local communities, and water utilities to manage increased pollution—often at taxpayer expense. Environmental advocates urge the EPA to maintain the 2015 standards or strengthen them, noting that clean water is a public good, not a cost to be minimized.

Meanwhile, Iowa's coal plants may continue to operate under less stringent rules, potentially endangering the Missouri, Mississippi, and Des Moines Rivers. The outcome of this regulatory battle will determine whether Iowans can trust their tap water and enjoy safe fishing and swimming in their rivers. As the EPA accepts public comments and prepares a final rule, the stakes could not be higher for the state's waterways and the people who depend on them.