The state’s largest provider of natural gas service is facing a potential fine of $400,000 from regulators over concerns that the company failed to answer too many telephone calls from its customers last year.

The Kansas Corporation Commission’s staff recommended the fine after Kansas Gas Service submitted a report on the quality of its service. In that report, the company acknowledged falling short of a KCC mandate that gas companies answer 95 percent of the customer calls. The fine is based on the percentage of calls unanswered; it could have ranged from $100,000 to $500,000.

The KCC, which regulates utilities, has yet to act on the proposed fine. Kansas Gas Service provides service to about 642,000 customers and is a division of ONEOK Inc., based in Tulsa, Okla.