Kinder Morgan Inc. was working with Illinois and federal agencies after a “suspected third-party line strike” caused natural gas to be released on a 20-inch diameter lateral of the Natural Gas Pipeline Company of America (NGPL) system in Lee County, IL.

The massive explosion, which could be seen for miles, killed two people and injured two others, according to the Lee County Sheriff’s Office. Officials said a tractor working in a field on a farm in a rural part of the county inadvertently struck the gasline, causing an explosion near the intersection of Franklin Grove Road and Route 38, between Dixon and Rochelle.

Following the incident, which occurred at about 9:35 a.m. CDT Tuesday, the impacted pipeline was isolated “and the area has been secured with local road closures.

“At this time, NGPL is investigating whether any required one-call notification was made as the company has no record of a current notification,” a KMI spokesperson said.

“Kinder Morgan is working with local, state and federal agencies on response efforts, and appropriate regulatory agencies have been notified. The company is working with customers on any impacts to service.”

The names of the deceased and injured were not released, pending notification to families. The injured workers were transported to a nearby hospital and later transferred to a trauma center in Rockford, IL. Lee County Sheriff John Simonton said one of the injured men was in critical but stable condition and the second man was listed in stable condition. The Illinois State Fire Marshal’s Office had investigators at the scene.

NGPL is considered the largest gas transporter into the high-demand Chicago market and one of the largest interstate pipeline systems in the country. NGPL has about 9,200 miles of pipeline, more than 1 million compression hp and 288 Bcf of working gas storage, according to KMI.