Panhandle Eastern Pipeline, the natural gas pipeline that ruptured and caused a large explosion and fire March 3 north of Mexico, returned to service Tuesday after a successful hydrotest on a 15-mile stretch of the pipeline last week.

Safety testing was conducted from March 31 to April 8 to verify pipeline integrity from the Centralia compressor station near Missouri Route Z to County Road 457 in Audrain County.

The rupture was found to be caused by a stress corrosion crack in the pipeline. The pipeline owners, Dallas-based Energy Transfer Partners, conducted four unsuccessful hydrotests on the pipeline before the April 8 success.

“The purpose of a hydrotest is to test the strength of the pipe using water by taking the pressure inside the pipe to a higher level than normal operations,” Energy Transfer Public Relations Representative Amanda Gorgueiro wrote in an earlier statement. “This will not only verify the integrity of repairs, it will also identify any areas we may want to proactively investigate further.”

Estimated costs associated with the March 3 rupture are $1.4 million. This includes property damage and gas loss from the rupture and fire. The heat of the fire cooked the road oil out of Missouri Highway 15 located between 50-75 yards from the rupture. The highway was closed for five days by the Missouri Department of Transportation while Energy Transfer conducted its initial investigation and to assess the road’s driving surface. Traffic was diverted to Missouri Routes E and T during the closure, while the initial investigation took place. All investigation activities were overseen by the Pipeline and Hazardous Materials Safety Administration.

Panhandle Eastern is a 1,300 miles system of four pipelines from Texas to Michigan.