Mayflower Oil Spill of 2013

In 2013, the Pegasus Pipeline (PPL), consisting of an 858-mile mostly underground pipeline owned by ExxonMobil Corporation (EM), was transporting diluted bitumen (a.k.a. “dilbit,” a chemically diluted form of highly viscous Canadian crude oil) south from Patoka, Illinois, to Nederland, Texas. On March 29, 2013, in Mayflower (Faulkner County), the PPL ruptured, spilling 3,190 barrels (134,000 gallons) of dilbit into the Northwoods subdivision. After flowing into a drainage ditch and an unnamed creek, the oil reached an inlet of Lake Conway known as Dawson Cove. The Mayflower Oil Spill was one of the worst environmental disasters in recent Arkansas history, causing an estimated $57 million in property damage and requiring a $55 million cleanup.

History of the Pegasus Pipeline
Starting in 2006, EM operated the PPL, which was originally three separate pipelines, as a single system. As a part of the 648-mile northern section of the PPL (NPPL), the Arkansas segment covered approximately 300 miles, extending from just north of Pocahontas (Randolph County) to near Ashdown (Little River County). The 211-mile southern section of the PPL was in Texas.

Constructed in 1947 from low-frequency electric resistance welded (LF-ERW) steel pipe, the NPPL was the oldest section of the PPL. Discontinued in 1970, LF-ERW pipe was known for its high susceptibility to failure due to its defective weld seams, which were prone to cracking and corrosion. In 1988, the federal Pipeline and Hazardous Materials Safety Administration (PHMSA), which regulates the operation of oil pipelines, warned the industry about the safety of pre-1970 LF-ERW pipes.

Before restarting the NPPL in 2006, which had been inactive since 2002 due to market conditions, EM conducted Hydrostatic Pressure Testing (HPT). Hydrostatic testing involves pumping water through an empty oil or gas pipeline at higher-than-normal pressure to check for cracks and leaks. After any needed repairs are made, pipelines are retested until they successfully pass HPT. In 2006, EM’s HPT detected eleven (some sources reported twelve) seam failures in the NPPL, which were repaired. While no problems were found in the Mayflower segment, two of the failures occurred in nearby sections of the pipeline.

Despite knowing the condition of the NPPL, EM reconfigured the PPL in ways that increased the amount of pressure inside the pipe. During the period from 2006 to 2009, EM began using the PPL to carry the Canadian dilbit, reversed the direction of its flow southward and increased its capacity from 65,000 barrels per day (BPD) to 95,000 BPD.

In 2010 and in February 2013, EM tested the PPL with in-line inspection tools, which are less expensive and disruptive than HPT but are not reliable for detecting dangerous cracks.

Response and Investigation
Within thirty minutes of the March 2013 spill, first responders—as well as federal, state, and local officials, and representatives from EM—arrived onsite. Because of the spilled oil and elevated levels of dangerous Volatile Organic Chemicals (VOCs) in the air, the Mayflower police evacuated the residents of twenty-two homes in the Northwoods subdivision, and the Environmental Protection Agency (EPA) began continuous air-quality monitoring. Observers reported that the ruptured pipe, which was shut down on March 29, stopped leaking at 3:00 a.m. on March 30.

In compliance with a PHMSA Corrective Action Order (CAO) issued shortly after the spill, EM hired Hurst Laboratories to conduct metallurgical testing on the broken pipe. Hurst concluded that the Mayflower section of the LF-ERW pipe failed because of its manufacturing defects, specifically identified as hook-shaped cracks in its weld seams.

The EPA, the Arkansas Department of Environmental Quality (ADEQ), PHMSA, the Arkansas Department of Health, EM, and other state and federal agencies formed the Mayflower Unified Command (MUC) to coordinate the cleanup and recovery response.

Northwoods Subdivision
After the MUC contained and recovered the oil using vacuum trucks, sorbents, excavators, and other tools, crews replaced the soil and sod, as well as the storm drains, driveways, and similar structures.

Exposure to the chemicals in the dilbit sickened a number of Northwoods residents. Many homeowners left the subdivision because of concerns about their long-term safety and the marketability of their properties. Exxon purchased and resold many of the homes and demolished three of the evacuated homes because of oil under their foundations.

Lake Conway
To prevent the oil from entering the main body of Lake Conway, the MUC, including staff members from the Arkansas Game and Fish Commission (AGFC), deployed thousands of feet of containment boom and built earthen dams at the head of Dawson Cove. Crews vacuumed, washed, and removed 1,829 tons of oiled soil, vegetation, and debris from the shoreline of Dawson Cove. Many oil-exposed birds, fish, reptiles, amphibians, and mammals died despite an organized wildlife rescue operation.

Based upon repeated testing of water and sediment samples, EM maintained that no oil entered the main body of the lake. Subsequent investigations, however, determined that the MUC’s containment measures were not entirely effective. In 2015, environmental scientists from Arkansas State University in Jonesboro (Craighead County) issued a report finding that exposure to oil-contaminated water and sediment caused sublethal levels of poisoning in the lake’s minnows and insect larvae.

PHMSA Violations and Fine (2015)
In 2015, PHMSA cited EM for nine violations of the pipeline safety regulations and fined the multibillion-dollar company $2.6 million for failing to properly maintain and prioritize testing of the NPPL in the face of known risks. Operators of high-risk pipelines—that is, pipelines that have known defects and are in highly populated and environmentally sensitive areas—must establish Integrity Management Plans that explain how they will prevent leaks and ruptures and conduct periodic fitness-for-service assessments. According to PHMSA, EM failed to consider the “historical incidence of seam failures” in the LF-ERW pipe and improperly determined that the Mayflower section was not susceptible to seam failure.

Exxon appealed PHMSA’s findings in the federal Fifth Circuit Court of Appeals. In 2017, a federal appellate judge overturned most of the violations and dismissed $1.6 million of the fine.

Consent Decree (2015)
In June 2013, the EPA and the ADEQ filed a joint complaint in the U.S. District Court for the Eastern District of Arkansas in Little Rock (Pulaski County). The EPA sought civil penalties and injunctive relief under the Clean Water Act (CWA), and the ADEQ sought civil penalties under state environmental law. Under the Oil Pollution Act of 1990 (OPA), the state of Arkansas sought reimbursement for spill-related damages. In 2015, a federal judge approved a $5.07 million consent decree, marking the first resolution of a major Mayflower oil spill–related lawsuit.

Specifically, EM agreed to pay $4.19 million in federal and state civil penalties ($3.19 million in federal, $1.0 million in state), $600,000 to fund a water quality improvement project for Lake Conway, and $280,000 for state litigation costs. Exxon was required to implement additional disaster preparedness measures and to “henceforth treat [the NPPL] as ‘susceptible to longitudinal seam failure’…for all risk assessment and operational purposes.” Exxon admitted no liability in the case.

According to the consent decree, the total amount of oil discharged was 3,190 barrels, which was less than EM’s original estimate of 5,000 barrels (210,000 gallons). Under the OPA and the CWA, the fines were based upon the amount of hazardous material discharged.

Lake Maumelle Threat
The NPPL crossed twenty-one watersheds in Arkansas, including that of Lake Maumelle. For Central Arkansas Water (CAW), the NPPL was a longstanding safety concern because Lake Maumelle supplies drinking water to 450,000 residents of central Arkansas, including in Pulaski County.

In July 2014, EM reopened the Texas-based southern section of the PPL. In 2016, Energy Transfer (ET) pipeline company bought the PPL from EM and renamed it the Permian Express Pipeline (PEP). In early 2020, ET announced plans to test the PEP, signaling a potential restart of the pipeline’s northern section. In response, CAW offered to purchase a section of the PEP from ET but received no response. In 2023, ET indicated that it had no plans to restart the PEP.

Consent Decree (2024)
In 2024, the Mayflower Oil Spill Trustees (MST), composed of the ADEQ, the AGFC, and the U.S. Fish and Wildlife Service (USFWS), prepared a final plan to restore the environment in accordance with the OPA. In October 2024, Chief U.S. District Court Judge Kristine G. Baker approved a $1.8 million consent decree between the MST and EM. Under the settlement, the MST planned to manage forty acres of forested habitat, convert a portion of agricultural land to migratory waterfowl habitat, and improve recreational fishing on Lake Conway.

The Future
The Mayflower Oil Spill is a powerful example of the damage wrought when oil pipelines fail. In 2013, the Mayflower spill sparked renewed criticism of the proposed Keystone XL pipeline project, which would have transported Canadian dilbit through Montana, Nebraska, and South Dakota, and was canceled in 2021. For the foreseeable future, despite environmental concerns and the push for renewable energy, oil pipelines remain essential for supplying global energy.

For additional information:
Consent Decree. U.S. and State of Arkansas v. ExxonMobil Pipeline Company and Mobil Pipe Line Company, No. 4:13-cv-0355 (U.S. District Court for the Eastern District of Arkansas, April 2015). https://www.epa.gov/sites/default/files/2015-04/documents/exxonmobil-cd.pdf (accessed September 17, 2025).

Consent Decree. U.S. and Arkansas Game and Fish Commission and Arkansas Department of Energy and Environment, Division of Environmental Quality, as Agencies of the State of Arkansas v. ExxonMobil Pipeline Company LLC and Mobil Pipe Line Company, No. 4-24-ev-473-KGB (U.S. District Court for the Eastern District of Arkansas, June 3, 2024). https://www.justice.gov/enrd/media/1354061/dl?inline (accessed September 17, 2025).

Department of Justice. “United States and Arkansas file Joint Complaint against ExxonMobil for Pegasus Pipeline Oil Spill in Mayflower, Arkansas, June 2013.” https://www.justice.gov/archives/opa/pr/united-states-and-arkansas-file-joint-complaint-against-exxonmobil-pegasus-pipeline-oil-spill (archived content, accessed September 17, 2025).

Douglass, Elizabeth. “Exxon Knew Its Ruptured Pipeline was Old, Defective and Brittle, and Still Added New Stresses.” Inside Climate News, August 12, 2013. https://insideclimatenews.org/news/12082013/exxon-knew-its-ruptured-pipeline-was-old-defective-and-brittle-and-still-added-new-stresses/ (accessed September 17, 2025).

Eifling, Sam, and Zahra Hirji. “A Neighborhood Shattered: Families Emptying Out of Oil-Hit Arkansas Town.” Inside Climate News, November 25, 2013. https://insideclimatenews.org/25112013/neighborhood-shattered-families-emptying-out-oil-hit-arkansas-town/ (accessed September 17, 2025).

Ellis, Dale. “Settling of Oil Spill Claims Sought.” Arkansas Democrat-Gazette, June 4, 2024, pp. 1A, 5A. Online at https://www.arkansasonline.com/news/2024/jun/03/officials-exxon-propose-consent-decree-to-settle/ (accessed September 17, 2025).

Environmental Protection Agency. “Final Pollution/Situation Report for Mayflower Oil Spill, 12/10/2013.” https://epaosc.org/sites/8502/files/exxonmayflower_polrep_16.htm (accessed September 17, 2025).

Gustin, Georgina. “Court Lets Exxon Off Hook for Pipeline Spill in Arkansas Neighborhood.” Inside Climate News, August 16, 2017. https://insideclimatenews.org/news/16082017/court-overturns-exxon-violations-fines-mayflower-arkansas-tar-sands–pipeline-spill/ (accessed September 17, 2025).

Hale-Shelton, Debra. “Exxon’s $500,000 is in for City Hall.” Arkansas Democrat-Gazette, June 23, 2016, pp. 1A, 3A.

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———. “Pipe’s Flawed Welds Caused 12 Test Failures.” Arkansas Democrat-Gazette, August 8, 2013, pp. 1A, 7A.

Hale-Shelton, Debra, and Jessica Seaman. “Routine, Risk Coexist at Spill Scene.” Arkansas Democrat-Gazette, April 2, 2013, pp. 1A, 5A.

Hardy, Benjamin. “Despite Settlement, ExxonMobil Faces Further Litigation over 2013 Mayflower Oil Spill.” Arkansas Times, April 30, 2015. https://arktimes.com/news/arkansas-reporter/2015/04/30/despite-settlement-exxonmobil-faces-further-litigation-over-2013-mayflower-oil-spill (accessed September 17, 2025).

Hardy, Benjamin, Sam Eifling, David Koon, and Elizabeth McGowan. “From the Vault: Revisiting the Mayflower Oil Spill 11 Years Later.” Arkansas Times, July 22, 2024. https://arktimes.com/arkansas-blog/2024/07/22/from-the-vault-revisiting-the-mayflower-oil-spill-11-years-later (accessed September 17, 2025).

Hasemyer, David. “6 Years After Exxon’s Oil Pipeline Burst in an Arkansas Town, A Final Accounting.” Inside Climate News, October 24, 2019. https://insideclimatenews.org/news/24102019/exxon-oil-spill-neighborhood-mayflower-arkansas-sealed-depositions-illnesses-fines/ (accessed September 17, 2025).

———. “Exxon Gets Fine, Harsh Criticism for Negligence in Pegasus Pipeline Spill.” Inside Climate News, October 2, 2015. https://insideclimatenews.org/news/02102015/exxon-gets-heavy-fine-and-criticism-pegasus-pipeline-spill-mayflower-arkansas-dilbit/ (accessed September 17, 2025).

Kennon, M. E., and J. L. Bouldin. “Aquatic Effects of a Localized Oil Spill on Lake Conway, AR and Its Tributaries.” Journal of the Arkansas Academy of Science 69 (2015): 60–67. Online at https://scholarworks.uark.edu/cgi/viewcontent.cgi?article=1012&context=jaas (accessed September 17, 2025).

Langhorne, Will. “Mayflower Recalls Oil Spill Decade Ago.” Arkansas Democrat-Gazette, March 27, 2023, pp.1A, 3A.

Mayflower Oil Spill Trustees. “Mayflower Oil Spill Restoration Plan Draft, June 2024.” https://www.doi.gov/restoration/mayflower-oil-spill-nrdar-trustees-release-draft-restoration-plan (archived content, accessed September 17, 2025).

Pipeline and Hazardous Materials Safety Administration. Mayflower Oil Spill Final Order. https://primis.phmsa.dot.gov/enforcement-documents/420135027/420135027_Final Order_10012015_text.pdf (accessed September 17, 2025).

Poole, Shelli. “I Met Neil Young on a Gravel Road in Mayflower.” MySaline.com, April 22, 2013. https://www.mysaline.com/i-met-neil-young-on-a-gravel-road-in-mayflower-today-yes-really/ (accessed September 17, 2025).

Melanie K. Welch
Mayflower, Arkansas