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Nicor Gas Completes Cast Iron Main Replacement Program

Gas infrastructure modernization ensures every customer’s energy needs are met safely and reliably now and well into the future

NAPERVILLE, Ill. – Nov. 28, 2018 – Today Nicor Gas marked the retirement of the last cast iron gas main from its system with a celebration at its headquarters in Naperville, Illinois. The completion of the main replacement program occurred last month in the communities of Harwood Heights and Norridge and city officials were on hand to celebrate, joining members of the Illinois Commerce Commission and other representatives from the state.

“This is a milestone achievement that was completed more than five years ahead of schedule as part of the Natural Gas Consumer Safety and Reliability Act,” said Pat Whiteside, vice president of business support at Nicor Gas. “Retiring the last of the cast iron main from our system helps to ensure the long-term safety and reliability of natural gas service for our customers, our neighbors and our communities.”

According to the U.S. Department of Transportation and Pipeline and Hazardous Materials Safety Administration (PHSMA), cast iron mains are among the oldest energy pipelines constructed and many were installed more than 60 years ago. However, the degrading nature of iron alloys, the age of the pipelines and pipe joint design have greatly increased the risk involved with continued use of such pipelines. 

At one time, Nicor Gas had more than 1,200 miles of cast iron main in its distribution system and began replacing it around the 1970s. For more than 40 years Nicor Gas replaced an average of 25 miles of cast iron main per year. But with the passing of the Natural Gas Consumer Safety and Reliability Act in 2013, which resulted in Nicor Gas’ Investing in Illinois program, the efforts to replace cast iron main doubled to more than 50 miles a year.

Today, Nicor Gas has no known low pressure cast iron main in its system because of the increased efforts of Investing in Illinois, a multiyear program to replace aging natural gas pipelines, move natural gas meters from inside homes and businesses to outside, upgrade natural gas storage systems and refurbish stations that regulate the natural gas pressure in our system.

According to PHMSA, 97 percent of the natural gas distribution pipelines in the U.S. today are made of plastic or steel, and only 3 percent made of cast iron remain.

To learn more about Nicor Gas’ system improvement initiative, Investing in Illinois, visit

About Nicor Gas
Nicor Gas is one of four natural gas distribution companies of Southern Company Gas, a wholly owned subsidiary of Southern Company (NYSE: SO). Nicor Gas serves more than 2.2 million customers in a service territory that encompasses most of the northern third of Illinois, excluding the city of Chicago. For more information, visit

About Southern Company Gas
Southern Company Gas is a wholly owned subsidiary of Atlanta-based Southern Company (NYSE:SO), America’s premier energy company.  Southern Company Gas serves approximately 4.2 million natural gas utility customers through its regulated distribution companies in four states with 774,000 retail customers through its companies that market natural gas and related home services. Other nonutility businesses include investments in interstate pipelines, asset management for natural gas wholesale customers and ownership and operation of natural gas storage facilities. For more information, visit Southern Company Gas at 


Media Contact:
Jennifer Golz
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