Root Causes

The investigation identified the following as primary root causes:

• Improper assembly of the installation equipment for the production tree by the on-site contract wellhead technician
• Inadequate setting of the barrier (tubing hanger assembly) designed to prevent the flow of liquids

Actions Taken

Chevron took immediate actions to address the identified issues. These steps include, among other things:

• Advanced assembly of installation equipment
• Enhanced barriers including the use, testing, and verification of downhole packers as a secondary barrier
• Reviewing and updating wellhead procedures and equipment
• Evaluating technological options to verify proper setting

illustration of bishop well control incident

Notes: 1) Cross-sectional views for illustration purpose only. Illustrations are not to scale and have been simplified for clarity. 2) B1 and C1 are identical, zooming in on the dashed rectangle in A.

This took place during completions, and not during fracking. There was no pipeline failure.

Total Fluid Release Volume Estimates

• Total fluid volume release estimated at +/-25,000 bbls (range 20,000-30,000 bbls)
• Total water volume estimated at +/-20,000 bbls (range 16,000-24,000 bbls)
• Total liquid hydrocarbon volume estimated at +/-5,000 bbls (range 4,000-6,000 bbls)

These volumes are consistent with our previous communications that the release comprised 80% produced water and 20% hydrocarbons.

Learn more about Chevron’s disclosure of frac fluid chemicals to ECMC

• As required by ECMC, Chevron submitted a Form 27 (Site Investigation and Remediation Plans) estimating total barrels recovered from the incident. This reported volume of 101,077 barrels consists of liquids recovered from the well site. This includes water used for equipment decontamination and fire suppression, and stormwater collection. It is industry practice to report unit measurements in barrels. Chevron will continue to comply with all regulatory reporting requirements.
• A full remediation plan for the well site is still under development. Initial work on the well site has been to decontaminate and demobilize equipment, install stormwater controls, and remove visually impacted surface material. Remediation work plans are submitted to ECMC for review prior to commencing work. Chevron remains fully committed to remediating the well site. 
• Approximately 25,272 cubic yards of solids have been removed from the well site as part of the initial response activities. This removal activity continues as part of our overall recovery efforts.
• All recovered waste is transported to a third-party disposal site for proper disposal, which is consistent with normal operational activities. The volume of liquid recovered is a separate measurement than the liquid volume that was released from the well.

• A Unified Command managed the initial response, comprised of the Weld County Office of Emergency Management, Chevron, the Galeton Fire Protection District, and the Environmental Protection Agency.
• Unified Command was stood down on Tuesday, April 15. Chevron transitioned from an Incident Management Team (IMT) to a Chevron Project Management Team approach.
• Participating agencies include Colorado Energy and Carbon Management Commission, Colorado Department of Public Health and Environment, Weld County Department of Public Health and Environment, Weld County Sheriff’s Office, Colorado State Patrol, Colorado Fire Prevention and Control, Colorado Parks and Wildlife, U.S. Department of Agriculture, Colorado Department of Agriculture, and the Colorado Division of Homeland Security and Emergency Management.

• The members of the Unified Command worked together to coordinate response efforts and share information. Chevron is currently managing the recovery phase.

Shortly after the incident started, local authorities initiated protocols to create a half-mile mile voluntary exclusion zone, reaching out to any residents in the area to alert them of the situation.

On April 11, 2025, the Bishop Well was safely sealed, which fully secured the well. The well was initially contained at approximately 3:30 p.m. MST on April 10, 2025.

The response to this incident began almost immediately and involved extensive planning and preparation to safely manage and resolve the incident.

Total Fluid Release Volume Estimates

• Total fluid volume release estimated at +/-25,000 bbls (range 20,000-30,000 bbls)
• Total water volume estimated at +/-20,000 bbls (range 16,000-24,000 bbls)
• Total liquid hydrocarbon volume estimated at +/-5,000 bbls (range 4,000-6,000 bbls)

These volumes are consistent with our previous communications that the release comprised 80% produced water and 20% hydrocarbons.

Learn more about Chevron’s disclosure of frac fluid chemicals to ECMC

We are happy to say that 10 of the 14 families are back in their homes.

We continue to actively work with the remaining residents on the next steps, including getting access to their properties to conduct assessments and cleaning. As with any property, the scope of work is customized recognizing that each property requires a separate plan.

We continue to work with land and agricultural property owners to conduct agriculture assessments. Similar to residential properties, we are conducting soil sampling, as required, to determine if any further work is needed.

We’ve conducted extensive soil sampling and air monitoring, and we remain committed to sharing key conclusions and data with all appropriate agencies.

Air monitoring continues in and around the area surrounding the site and the community with 5 stationary monitoring stations deployed. We also have analytical air samples (summa canisters) at each of those locations.

Chevron has not collected any readings that pose a threat to human health based on EPA standards.

Greeley Canal #2
We conduct weekly site walks with NCLP along the canal, performing visual impact assessments. We have a surface water sampling process program agreed to with NCLP which includes collecting daily samples upstream and downstream of the site to determine if there are any impacts.

Willow Creek
We continue to take daily samples both upstream and downstream.

As part of the ECMC remediation and reclamation process, Chevron is required to provide an estimated date of completion. We provided a conservative estimate given that the sampling and plan development is still ongoing. The exact timeline of the remediation, monitoring, and reclamation steps for each site will be updated as we get additional data and finalize plans.

Chevron has a team focused on remediation and reclamation projects. This team safely and responsibly decommissions and removes wells, tanks and pipelines, then reclaims the land for other purposes. Since 2016, we have plugged and removed an average of 500 wells per year in Colorado. In 2024, we plugged and removed ~750 wells. This program helps reclaim thousands of acres for other uses, such as agriculture, rangeland, and wildlife habitat, significantly reducing our carbon intensity and enhancing the local environment.

As part of these efforts, our Chevron Wildlife Program includes an assortment of programs that provide protections, mitigations, and improvements to support wildlife and their habitats. These programs are designed to provide science-based datapoints to aid in future site selection; identify focus areas for mitigation efforts; and implement enhancements that will produce beneficial impacts to wildlife and their habitats.

We are collaborating with many entities such as Colorado Parks and Wildlife, University of Montana, Boone and Crockett Wildlife Conservation Program, and Colorado Cattlemen’s Agricultural Land Trust to bring together the expertise and vision necessary to execute the Comprehensive Wildlife Plan.

Overview of the site remediation closure process

Soil sampling map

Soil sampling table

The final results of the lab data set will determine any next steps for soil sampling. If there are exceedances of ECMC standards that are related to the event and not consistent with existing background soil composition, a remedial work plan will be developed and submitted to ECMC for approval. This will include additional delineation sampling, execution of the remedial work plan, and confirmation sampling.

There may also be additional sampling required by ECMC, even if there are no exceedances.

To date, we have found a limited number of exceedances and are working to implement the necessary remediation plans.

The ECMC regulatory values are used as screening levels to determine if additional assessment is necessary.

The ECMC regulatory values are used as screening levels to determine if additional assessment is necessary.

If remediation is required, a plan will be developed after receipt of final validated data and then submitted to ECMC for review and approval. We are following an established ECMC process for environmental remediation projects.

Validation of sampling data will determine the final results data set and next steps for your property. A remedial work plan will be developed and submitted to ECMC for approval. This will include additional delineation sampling, execution of the remedial work plan, and confirmation sampling.

The timeline for final results and next steps is specific to each parcel. We’re actively working to finalize all data and proceed through the ECMC remediation process.

The established ECMC process will determine when regulators provide an assessment of the property.

Water Management

• Lined the north ditch.
• Actively collecting stormwater and trucking it off-site 24/7 for disposal.

Soil and Site Preparation

• Scraped and disposed of the top 12 inches of soil from the east berm and highway right-of-way.
• Scraped and disposed of soil from the fields north and south of the pad, with post-removal sampling completed.
• Scraped and disposed of the top 3 to 5 inches of soil off the pad for removal.

Monitoring and Analysis

• Chevron's hydrologists and reclamation specialists have walked the site and mapped out the surface features.
• Installed 10 groundwater monitoring wells around the pad.
• Clearing areas for borehole drilling and drafting an analysis plan for ECMC approval.

We plan to complete all 16 wells. Once the wells are complete, we can remove the soundwalls. We will implement added safeguards such as installing an additional downhole barrier on all the wells.

We plan to commence operations at two sites approximately three miles north of the Bishop Well. We expect drilling to begin on site DP 825 and fracking on site DP137 beginning the last two weeks of June.

You may see equipment being positioned in the next few weeks on both sites preparing to start operations.

• Call Chevron claims line at 877-359-1285.

• We don’t expect there to be risks to your animals.
• Should you have any additional questions, please call Chevron claims line at 877-359-1285.

Validation of this data will determine the final results data set and next steps for your property. A remedial work plan will be developed and submitted to ECMC for approval. This will include additional delineation sampling, execution of the remedial work plan, and confirmation sampling.

The timeline for final results and next steps is specific to each parcel. We’re actively working to finalize all data and proceed through the ECMC remediation process.

If remediation is required, a plan will be developed after receipt of final validated data. We will contact you to discuss next steps, timing, and the ECMC approval process. We are following an established ECMC process for environmental remediation projects. This is a multi-step process, and the timeline depends on the complexity of the work.

Overview of the site remediation closure process

• Chevron has not collected any readings that pose a threat to human health based on EPA standards.
• If you have questions about your specific situation or condition, please call your medical provider.

• If you have concerns about your livestock, contact your veterinarian. If you have been impacted, please contact the Bishop Well Incident Claims Line at 877-359-1285. 

• If you have concerns about your livestock, contact your veterinarian. If you have been impacted, please contact the Bishop Well Incident Claims Line at 877-359-1285.   

It is unlikely that well water would be affected by this incident. If you have concerns about your well, Weld County Department of Public Health and Environment has a free testing program. You can learn more about this service on the Weld County website. However, the presence of any contaminants in your well water does not necessarily mean that your well was affected by this incident. A proper evaluation of the source of any contaminants would still have to be done.

Numerous governmental agencies are monitoring this incident and wildlife in the area. This includes state veterinary services, Colorado Parks and Wildlife, and Colorado Department of Agriculture.