NTSB/PAB-01/02 

National Transportation Safety Board 

Washington, D.C. 20594 

Pipeline Accident Brief

Pipeline Accident Number: DCA-00-MP-004 

Type of System: Hazardous liquid 

Accident Type: Pipe failure and leak 

Location: Winchester, Kentucky 

Date and Time: January 27, 2000, 12:12 p.m. central standard 

time (CST) 

Owner/Operator: Marathon Ashland Pipe Line LLC 

Fatalities/Injuries: None 

Damage/Clean Up Cost: $7.1 million 

Material Released: Crude oil 

Quantity Released: About 489,000 gallons 

Pipeline Pressure: 606 pounds per square inch, gauge, (psig) 

 at site of failure

Component Affected: 24-inch-diameter, API 5L, X-52, 0.250-inch-wallthickness, steel pipe 

The Accident

About 12:12 p.m. CST1 on January 27, 2000, a Marathon Ashland Pipe Line LLC 

(Marathon Ashland) 24-inch-diameter pipeline that runs 265 miles between Owensboro 

and Catlettsburg, Kentucky, ruptured near Winchester, Kentucky. The ruptured pipeline 

released about 11,644 barrels (about 489,000 gallons) of crude oil onto a golf course and 

into Twomile Creek. No injuries or deaths resulted from the accident. As of 

December 13, 2000, Marathon Ashland had spent about $7.1 million in response to the 

accident. 

Preaccident Information

The pipe was 0.250-inch-wall-thickness, 24-inch-diameter, steel pipe. It was 

constructed in 1973. In the area of the rupture, the pipeline ran through a layer of shale 

and rested on cinderblock-size pieces of Styrofoam. These Styrofoam “pillows” were 

installed to keep the pipe from lying directly on the shale. The pipeline had a maximum 

operating pressure of 780 psig. 

 

1

 All references to time in this report are CST. Although the Marathon Ashland operations center is in 

the eastern time zone (in Findley, Ohio), this pipeline originates in the CST zone. 
NTSB/PAB-01/02 

2 

In January 1997, a contractor’s magnetic flux standard resolution inline inspection 

tool was run through the entire pipeline. Excavations were then made at locations along 

the pipeline where the inspection tool indicated significant anomalies. At the site where 

the pipeline ruptured, the 1997 inspection data showed an anomaly that the contractor had 

interpreted as a “dent.” The pipeline had not been excavated at this location because the 

dent did not appear to meet the repair criteria being used at the time. The repair criteria 

used required that, for a dent to be repaired, it had to be deeper than 2 percent of the 

outside diameter of the pipe. 

Leak Reporting and Response

During the morning of January 27, 2000, the pipeline had been shut down for 

previously planned maintenance work at the Catlettsburg terminal. The shutdown of the 

line began at 6:59 a.m., and the line was out of operation until 11:12 a.m. At this time, a 

controller at the Marathon Ashland operations center in Findlay, Ohio, opened manifold 

valves at Owensboro and Catlettsburg to allow the pipeline to return to normal 

operations. 

At 11:14 a.m., the controller began to restart the pipeline. About 11:30 a.m., a 

pipeline leak monitor (PLM) alarm sounded in the Findlay operations center and flashed 

on the supervisory control and data acquisition (SCADA) screen.2 This alarm indicated 

that the liquids into and out of the pipeline were not in balance. After the controller 

focused on some pressure set points and flow rates to reestablish balance, he resumed 

starting additional pumping units on the line. About 11:52 a.m., the SCADA system 

flashed “NORMAL” on the screen, indicating that the alarm had cleared and the flow 

rates were in balance. The controller continued to monitor pressures at stations along the 

line. At 12:00 noon, a PLM alarm again sounded, indicating that the parameters for the 2-

hour and 4-hour line balance were still showing an imbalance on the system. (The 

controller explained during a postaccident interview that he had expected the PLM alarms 

to sound during the startup of the system, so he was not surprised by the alarms 

sounding.) SCADA records show that the pipeline rupture occurred between the 

Marathon Ashland Tates Creek and Preston Stations at approximately 12:12 p.m. A PLM 

alarm displayed almost immediately after the pipeline ruptured. 

About 12:37 p.m., the controller, uncomfortable about the lower-than-expected 

pressures at pumping stations along the pipeline and a lost flow rate at Catlettsburg, 

started to shut the system down. Additional PLM alarms, showing losses, displayed at 

12:45 and 12:54 p.m. 

 

2

 Pipeline controllers use the SCADA system to remotely monitor and control movement through pipelines. Using 

the SCADA system, controllers can monitor flow rates and pressures along the lines and control valves and pumps to 

adjust the flow at pump stations and other locations throughout the pipeline system. 
NTSB/PAB-01/02 

3 

About 1:00 p.m., the controller paged the operations supervisor and, shortly 

afterwards, the supervisor came into the Findlay operations center. After the controller 

and the supervisor had discussed the situation and reviewed the data, they called the area 

supervisor for this pipeline segment. 

The two supervisors discussed the situation and agreed that they should pressure 

up the pipeline to monitor the pressures. The downstream valves at Catlettsburg were 

closed about 1:02 p.m. About 1:28 p.m., a single pumping unit at Owensboro, the 

originating pump station, was started to put pressure on the pipeline. Pressures along the 

pipeline were observed and recorded. About 1:00, 1:38, 1:40, and 1:44 p.m., PLM alarms 

sounded and showed on the SCADA screen. At 1:46 p.m., and again at 1:57 p.m., the 

pressures were recorded. 

About 2:00 p.m., the controller expressed concern to the operations supervisor 

that they had put about 1,000 barrels of crude oil into the pipeline, but pressures were not 

rising as expected. After making a phone call to the area supervisor, the operations 

supervisor told the controller to shut down the pipeline. The shutdown was accomplished 

about 2:05 p.m. 

Shortly afterwards, at 2:11 p.m., the Winchester Fire Department called the 

pipeline operations center in Findlay, Ohio, to report the odor of gas in the air. The 

operations center immediately relayed this information to the area supervisor, who 

dispatched a four-person crew to close the two manual valves nearest the leak site. 

Marathon Ashland employees closed these manual valves at 3:30 p.m. 

About 2:20 p.m., a landowner downstream of the leak site telephoned the Findlay 

operations center to report oil flowing onto his property. The operations supervisor told 

the controller to automatically shut the mainline block valves at the Preston and Tates 

Creek Stations. 

Postaccident Examination of the Failed Pipe

The rupture was found on the bottom of the pipe. (See figure 1.) Postaccident 

laboratory examination of the pipe showed transgranular cracks that had the appearance 

typical of fatigue progression. The combined depth of the progressive cracks in the areas 

of maximum penetration was about 90 to 95 percent of the pipe wall thickness. 
NTSB/PAB-01/02 

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Figure 1. Photograph of ruptured pipe; arrow indicates rupture site 

Primary and secondary origin areas of fatigue cracking were found at the edges of 

a dent in the pipe wall. The dent was consistent with contact with a hard object, although 

no hard object likely to have caused it (such as a rock) was found during the 

investigation. Numerous secondary cracks were in the vicinity of the two origin areas. 

Postaccident Developments

After the accident, the U.S. Department of Transportation’s Research and Special 

Programs Administration issued a Corrective Action Order requiring Marathon Ashland 

“to take the necessary corrective action to protect the public and the environment from 

potential hazards associated with its 24-inch pipeline.” In part, these actions included: 

maintaining a 20-percent operating pressure reduction; conducting all analysis necessary 

to determine an interim maximum operating pressure; developing and implementing a 

work plan for the testing and repair or replacement of sections of pipe with significant 

defects; evaluating the effectiveness of full encirclement sleeves for repairing significant 

defects identified by a transverse flux inline inspection tool; and submitting a report of 

the results of all removal, testing, and analysis performed under the work plan to the 

regional director of the Office of Pipeline Safety. Marathon Ashland ran 

slope/deformation and transverse flux inspection tools in the pipeline and reported the 

findings to the Office of Pipeline Safety. (These tools are used to discover anomalies in 

the line, such as dents, corrosion, or cracking.) As a result of these internal inspections, 

anomalies meeting the repair criteria for the entire pipeline were reviewed, inspected, and 

repaired. 

Postaccident Training

Before the spill, Marathon Ashland had allocated funds for and ordered (1) a 

SCADA training simulator for its controllers and (2) a full-time training supervisor. The 

training supervisor began duties in March 2000. The simulator arrived on May 15, 2000, 
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5 

and the first pipeline simulation model, of a Marathon Ashland 10-inch products system, 

was used to train 43 controllers. A second pipeline simulation, of a Marathon Ashland 

22-inch crude oil system, was installed on October 6, 2000. As of January 2001, four 

controllers had completed training on this second simulation. Marathon Ashland intends 

the simulator training to help its controllers recognize and react to problems more 

effectively. 

Probable Cause

The probable cause of the accident was fatigue cracking due to a dent in the pipe 

that, in combination with fluctuating pressures within the pipe, produced high local 

stresses in the pipe wall. Contributing to the severity of the accident was the failure of the 

controller and supervisors to timely recognize the rupture, shut down the pipeline, and 

isolate the ruptured section of the pipeline. 

Approved: May 3, 2001