(Reuters) – Norfolk Southern Corp on Monday said it plans to add about 200 detectors to its tracks that will help identify overheated bearings as the railroad operator came under fire after a derailment in Ohio spewed toxins into the air and water.

The company said it was evaluating the distance between hot bearing detectors, which currently averages 13.9 miles on its “core network”, as part of a six-point safety plan based on the preliminary findings of the National Transportation Safety Board (NTSB).

The move comes as the company faces criticism from regulators and enraged residents of East Palestine, Ohio, who say their livelihoods had been ruined and that their homes were worth nothing because they live near the derailment site.

The company’s chief executive has apologized for the Feb. 3 derailment of its train, which led to cars carrying toxic vinyl chloride and other hazardous chemicals to spill and catch fire.

Norfolk will also examine every location where the distance is more than 15 miles and develop a plan to deploy additional detectors where practical, the company said on Monday, without disclosing any details of the investment.

Hot bearing detectors transmit audible alarm messages to crew members alerting them to inspect a hot axle.

Norfolk said it is also working with manufacturers to accelerate testing and deployment of safety technology that could scan a greater cross-section of a railcar’s bearings and wheels.

The company plans to quantify the costs of cleaning up the East Palestine site no later than when it reports its first-quarter earnings, it said last month.

Meanwhile, the NTSB is investigating another derailment of a Norfolk Southern train near Springfield, Ohio on Saturday.

(Reporting by Nathan Gomes in Bengaluru)