Norfolk Southern said it is changing its requirements on how longer trains' power must be distributed.
SPRINGFIELD, Ohio. -- The National Transportation Safety Board is sending investigators to west central Ohio Monday after a Norfolk Southern freight train derailed there over the weekend, prompting calls to shelter in place before authorities announced the wreck was not hazardous and there was no environmental harm, CNN reported.
The derailment near Springfield, Ohio, just 1,000 feet from nearby homes, happened Saturday, just one month after another Norfolk Southern train wreck across the state in East Palestine, Ohio, put the company under intense scrutiny over contamination that seeped into the small town.
The 212-car freight train was southbound through Clark County Saturday, en route to Birmingham, Alabama, when 28 of its cars derailed, downing large high tension power lines, knocking out power to some residents and temporarily prompting shelter-in-place orders to homes within 1,000 feet, authorities said.
The cause of the derailment remains under investigation, according to Norfolk Southern.
Crews have determined there were no spills from the derailed cars, officials said.
"There was no release of any chemical or any hazardous material to the soil, to the air, to the water," Ohio Environmental Protection Agency Director Anne Vogel said Sunday.
Four of the derailed cars were empty tanker cars carrying minimal residual product in "very minor amounts" that "dried very quickly," Springfield Fire Assistant Chief Matt Smith said, adding that his team checked the crash site and determined that nothing had spilled onto the ground.
The four tank cars with residue had previously been carrying diesel exhaust fluid and an additive commonly used in wastewater treatment, but were empty when they derailed, according to Norfolk Southern General Manager of Operations Kraig Barner.
"There's always a small residual amount left in the tanks," Smith told CNN. "The derailed tank cars are not hazardous or pose a risk to the public."
One car was carrying PVC pellets that affected the soil at the crash site, Vogel noted, adding that the EPA "will be onsite ensuring that as cars are removed by Norfolk Southern that the soil is not impacted under the ground."
After the derailment, authorities at a Sunday news conference sought to assure the local community in Clark County that their air, water and soil are safe.
"Since there have been no releases, we're looking at clean air, clean soil and clean water for our residents," Clark County Health Commissioner Charles Patterson said. "Technicians will continue to be on site to ensure that there isn't any contamination that has been missed."
"There have been multiple sweeps by multiple teams of technicians, hazmat and Ohio EPA to ensure that there aren't any chemicals present in the soil, air or water that would harm the public here in Clark County," Patterson added.
The assurances come as crews more than 200 miles away in East Palestine, Ohio, are still working to clear contaminated soil and liquid from the toxic wreck of another Norfolk Southern train that derailed on February 3.
The East Palestine derailment fueled outcry among residents who have complained of symptoms, including headaches and coughing after the fiery crash. The train was hauling the dangerous chemical vinyl chloride -- which was released and burned to prevent a potentially deadly explosion -- and other chemicals that are feared to have leaked into the surrounding ecosystem.
When asked if there were hazardous materials carried in other parts of the train that derailed in Clark County, Barner said Sunday there were a few propane and ethanol tankers on the train, while the rest was mixed freight, including steel and finished automobiles.
But he emphasized that none of the derailed cars were carrying hazardous material.
Last month's derailment put rail safety under the spotlight and raised questions about regulations surrounding the transport of hazardous materials. Data from the Federal Railroad Administration Office of Safety Analysis shows there have been at least 1,000 derailments in the United States each year during the past decade.
On Saturday, Transportation Secretary Pete Buttigieg said officials from the Federal Railroad Association will also travel to Clark County.
"I have been briefed by FRA leadership and spoke with Gov. DeWine to offer our support after the derailment today in Clark County, Ohio. No hazardous material release has been reported, but we will continue to monitor closely and FRA personnel are en route," Buttigieg said in a tweet on Saturday.
Norfolk Southern is also changing its policies on the power and braking controls required on their longer trains.
They are going to mandate that all trains they operate that are longer than 10,000 feet be operated with distributed power.
Distributed power units, or DPU's, are essentially an extra power boost in the middle of the train, which helps control acceleration and braking, according to the NTSB.
These distributed units are wirelessly controlled from the leading locomotive in both power and braking as needed to assist in the management of in-train forces.
This allows the crew to not only haul their load, but also, helps handle that girth by spreading the power more evenly throughout the snaking consist -- and, perhaps, help avoid some future derailments.
"At Norfolk Southern, the safety of our crews and the communities we serve comes first," a company spokesperson said in a statement to ABC. "Part of enhancing safety is continuously evaluating how we operate our network, and we have been examining immediate ways to move that goal forward."
ABC News contributed to this report.
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