Tokyo Electric Power Company Holdings Inc. on Monday began visiting some 41,000 households around the company's idled nuclear power plant in Niigata Prefecture to apologize for providing erroneous information on a key safety issue.

Tepco, also the operator of the disaster-hit Fukushima Daiichi nuclear complex, is seeking to restart its Kashiwazaki-Kariwa plant in central Japan, but locals have been upset over the recent revelation that the company kept undisclosed since 2014 data over the poor quake-resistance level of an emergency response center building.

The utility filed for state safety assessment of the Nos. 6 and 7 reactors at the Kashiwazaki-Kariwa plant in September 2013. All Japanese reactors currently have to satisfy a set of new safety requirements introduced after the 2011 Fukushima nuclear crisis.

Tepco initially explained to nuclear regulators that it would use an existing quake-proof building at the plant's premises as a center to deal with serious accidents.

But its analysis in 2014 showed that the building did not meet the required seismic standard and the company did not report the data to regulators until February this year.

Tepco subsequently said it will give up its plan to use the quake-proof building as the center to deal with emergencies and will instead use an area to be newly set up inside the building housing the No. 5 reactor.

The utility has denied that it "intentionally sought to hide" the information in question. But concerns linger among locals about whether the company can be trusted as a nuclear power plant operator, given its past history of cover-ups.

Tepco employees have visited all of the households in the city of Kashiwazaki and the village of Kariwa twice since 2015 to explain the nuclear power plant's safety measures and the progress of the safety assessment by the Nuclear Regulation Authority.

Following the latest blunder, they plan to visit about 41,000 houses through September, according to Tepco.

Tepco is eager to bring the idled Kashiwazaki-Kariwa plant back online as it is facing a tough business situation due to the massive costs stemming from the Fukushima crisis that began in March 2011. Restarting its reactors will help the utility cut huge costs for importing fuel for fossil fuel power generation.

The Nos. 6 and 7 reactors are advanced boiling water reactors and the newest among the seven units at the Kashiwazaki-Kariwa plant, one of the world's largest nuclear power plants, with a combined output capacity of 8.2 million kilowatts.