In 2015, the U.S. Environmental Protection Agency (EPA) issued a new rule addressing the handling, storage and disposal of coal combustion residuals (CCRs). CCRs are the materials that remain after coal is burned.

Two Northeastern 3&4 Plant ash storage sites are included in the CCR monitoring program:

  • The bottom ash pond and
  • The landfill.

Both storage sites are in active use. Northeastern Plant now uses dry fly ash handling. Fly ash is stored in a lined landfill. The landfill has an “intermediate” liner. The landfill was not lined when it was first built. Northeastern Plant added the intermediate liner and now places all material over the liner.

In 2017, Northeastern Plant provided nearly 46,000 tons of CCR material for beneficial reuse.

February 2019

In 2018, PSO continued its groundwater monitoring activities around Northeastern 3&4 Plant’s coal ash storage sites. We analyzed this data relative to EPA drinking water standards and/or with groundwater protection standards.

Analysis of this data by an independent third party indicates that the bottom ash pond potentially is causing the level of lithium in groundwater within the plant site to rise above EPA standards. We did not find impacts from the landfill.

PSO will cease operating Northeastern 3&4 in 2026. At that time, we will stop placing material in the pond and close the site. Meanwhile, we will begin taking steps to mitigate groundwater impacts. We are proactively meeting with plant neighbors and community leaders to answer questions and discuss next steps.

March 2018

Public Service Company of Oklahoma (PSO) has completed the first steps in the new groundwater monitoring program under this rule.

PSO took a series of groundwater samples at the boundaries of both ash storage sites. We took some samples before the groundwater passed beneath the ash storage sites. (The reports refer to this as up-gradient.) We took other samples after it passed beneath the sites (down-gradient). We used the data to establish baseline levels for 21 different substances in the groundwater. Moving forward, we will use these baselines to help determine if our ash storage sites are impacting the groundwater.

It is important to remember that variations in the level of these substances in groundwater are natural and occur for many reasons.

The initial data at Northeastern Plant show potential groundwater impacts very close to our storage sites. This led us to expand our groundwater monitoring program at Northeastern 3 & 4 to look at 21 different substances in the groundwater at the plant.

We are working to understand what the numbers mean. We will do additional monitoring and analysis to determine if there are groundwater impacts from our storage sites farther from the immediate area.

We proactively reached out and met with plant neighbors and community leaders to answer questions about the data collected so far and to discuss next steps.

An independent third party successfully completed an Alternate Source Demonstration for the landfill at Northeastern Plant. The successful demonstration identifies other factors that could impact sampling results as the groundwater passes the CCR storage sites.

The plant will continue sampling groundwater at the landfill to determine any future need for additional monitoring.

November 2018

The CCR rule established location restrictions for coal ash storage sites. It requires that storage site locations be evaluated regarding proximity to groundwater aquifers, wetlands, fault areas, seismic zones and unstable areas (example: presence of quicksand).

AEP and PSO recently completed the required review of location restrictions for Northeastern Plant’s CCR storage sites. This review found:

  • The Northeastern bottom ash pond is separated from the uppermost aquifer by less than the five feet specified by the rule. It does meet the other four restrictions.
  • The Northeastern landfill meets all location restrictions.

  • PSO will continue to test water from all of these wells twice each year.
  • Unit 4 was closed in 2016. Northeastern 3&4 Plant has a complete closure date of no later than 2026. At that time, we will stop putting material into the bottom ash pond and the landfill and will begin closure activities.
  • PSO will develop a mitigation plan to address the groundwater impacts. We will seek public input before making a final decision as to what measures we will take to mitigate groundwater impacts.


Additional Information