(NewsNation) — It’s been almost two weeks since a Norfolk Southern train carrying toxic chemicals derailed in East Palestine, Ohio, and many community members are still looking for answers.

The release of hazardous material forced residents to evacuate, but even though that order has been lifted, there are ongoing concerns over air and water quality.

Here’s what we know about the accident and the railroad company whose train derailed.

what is norfolk southern?

Formed in 1982, Norfolk Southern Railway is one of seven Class 1 freight railroads in the United States. The Atlanta-based company has more than 19,000 employees and operates approximately 19,300 route miles across 22 states, primarily in the southern and northeastern U.S.

what caused the derailment?

Officials are still investigating what caused the derailment, although the National Transportation Safety Bureau (NTSB) said Tuesday that surveillance video appeared to show an overheating wheel bearing moments before the accident.

Security footage obtained by the Pittsburgh Post-Gazzette suggests the train may have traveled at least 20 miles with a malfunctioning axle. The video shows the underside of one railcar glowing brightly from what appears to be a fiery axle.

The NTSB is expected to release its preliminary report in two weeks. Northfolk Southern said it has been cooperating with the investigation.

did train length play a role?

It’s too soon to know what role, if any, the length of the Norfolk Southern train played in the derailment, but some experts NewsNation spoke to believe it was a contributing factor.

At 150 cars long, the train in East Palestine was more than twice the average length of freight trains operated by major railroads in 2017.

Longer trains are harder to stop in the event of an emergency and there are more components that can malfunction, retired rail engineer Jeff Kurtz told NewsNation.

Railroads haven’t been shy about the move toward longer, heavier trains in recent years, which have boosted productivity, efficiency and profits.

In its 2021 annual report Norfolk Southern said it had reached “record productivity levels” by “improving” average train weight 21% and average train length 20% over a three year period.

has this happened before?

It’s not the first time a Norfolk Southern train carrying hazardous material has derailed. In 2017, 30 cars went off the tracks in Pell City, Alabama, releasing approximately 60 tons of sodium chlorate. The incident triggered a precautionary evacuation at a nearby gas station.

A 2019 Norfolk Southern derailment near Perry, Georgia, ruptured a nearby natural gas pipeline, resulting in an estimated $5 million in railroad damages. That accident did not require an evacuation.

how common are train derailments?

In 2021, there were 1,087 train derailments in the United States, according to the Bureau of Transportation Statistics (BTS). In the vast majority of those incidents — over 90% — there were no reported injuries.

The number of train derailments has fallen over the years. As recently as 2006, there were almost 2,200 derailments, though freight rail traffic was considerably higher than it is today.

Norfolk Southern had 156 derailments in 2021 which was third most among the major railroads but lower than its average over the last ten years.

Despite the relative frequency of derailments, rail accidents involving hazardous materials are exceedingly rare. According to the Department of Transportation, rail remains the safest way to transport large quantities of chemicals over long distances.

how has the company responded?

Hundreds of frustrated East Palestine residents turned out for a community meeting Wednesday night hoping to get their questions answered.

After reportedly pushing to change the format from a moderated town hall to an open house, representatives for Norfolk Southern did not attend the gathering citing concerns for employee safety.

The next morning, Norfolk Southern’s CEO Alan Shaw issued a statement vowing to “not walk away” from the village in eastern Ohio.

“We are here and will stay here for as long as it takes to ensure your safety and to help East Palestine recover and thrive,” Shaw wrote.

The company has distributed $1.5 million in direct financial assistance to more than 1,000 families and established a separate $1 million fund for the community.

Norfolk Southern said it’s worked with the government to complete more than 400 in-home air tests and continues to sample the area’s drinking water supply.

is norfolk southern being sued?

At least six federal lawsuits have been filed against Norfolk Southern in the U.S. District Court’s Northern District of Ohio as of midday Thursday.

The suits allege that the railroad company was negligent in its handling of the train derailment which resulted in hazardous material spilling into the area.

One of the country’s largest personal injury law firms, Morgan & Morgan, filed a class action lawsuit Wednesday. The suit alleges the railroad’s clean up efforts compounded the problem and led to a “1-million-pound chemical burn pit.”

“I’m not sure Norfolk Southern could have come up with a worse plan to address this disaster,” attorney John Morgan said in a statement.

The complaint accuses the company of choosing a cheaper, less safe containment method that prioritized “restoring train service and protecting share holders” over the safety of nearby residents.

Morgan & Morgan has successfully litigated similar cases before, including a $1.8 billion class action settlement resulting from the Porter Ranch natural gas leak in 2015.