What if a train derailment like Ohio’s happened in Philly?

Railroad tracks snake through the city’s residential neighborhoods from South Philadelphia to Center City, and the trains that use them may be hauling hazardous materials right through those communities.

If a train carrying a dangerous chemical derailed in Philadelphia — as happened in Ohio on Sunday — and the material escaped, people nearby could start feeling the effects before emergency responders had time to react, said Joanne Kilgour, executive director of the Ohio River Valley Institute.

“The chance that you would experience a serious health impact is very high even if you have a chance at survival,” Kilgour said.

Industry experts say such incidents are rare, and no injuries have been reported in the Ohio accident.

The derailment Sunday in East Palestine, Ohio, near the Pennsylvania border, involved the risk of a deadly explosion and the release of a toxic chemical, vinyl chloride. It’s a colorless, sweet-smelling gas that cause dizziness, headaches, and sleepiness in small amounts and can kill with heavy exposure. The derailment happened in a sparsely populated area and up to 2,000 people live in the evacuation zone. East Palestine is home to 4,800, according to the Associated Press.

If dangerous chemicals escaped in a Philadelphia train incident, the number of people needing evacuation could be many times that. One Penn Environment study from 2015 estimated more than 700,000 people lived within a half mile of a potential accident involving a train transporting oil.

» READ MORE: Residents kept out as air is checked near derailed Ohio train

Kilgour noted the logistical obstacles an evacuation effort would face. Emergency workers would have to account for people with disabilities, pets, and those who needed certain medications, and people without easy access to transportation.

“Of course, we’re concerned something like this could happen here,” said Russell Zerbo, an advocate with the Clean Air Council. “It could happen anywhere whenever you’re transporting these chemicals. It’s a constant risk.”

The American Association of Railroads emphasized incidents involving hazardous materials are very rare. Train accidents included the release of hazardous materials less than 1% of the time over the last decade, said Jessica Kahanek, a spokesperson for the industry organization. Class I railroads spent $439 billion since 2000 on rail infrastructure maintenance and capital projects, the association reported. In that time, the number of accidents dropped 33%.

» READ MORE: Ohio train derailment involves same chemical as one released in the Philly region a decade ago

A few years after a 2012 derailment in Paulsboro, Gloucester County, that also involved vinyl chloride escaping, the freight rail industry adopted the federal guidelines that establish how to respond to emergencies and include minimum safe isolation and evacuation distances when a train accident involves the release of an array of materials, including toxic gas, flammable material, and explosives.

An industry app, AskRail, gives first responders information about a railcar’s contents and recommends isolation zones when an accident happens, Kahanek said. That system was used in Ohio.

The population density of an area a train is traveling through is a factor in freight rail’s safety planning, Kahanek said.

If an accident were to happen in Philadelphia, city public safety officials, the Philadelphia Fire Department, and hazardous-materials experts would likely coordinate with the owner of the train and tracks to help people in affected neighborhoods, said Jeffrey Kolakowski, spokesperson for Philadelphia’s Office of Emergency Management.

The city has evacuation plans that can be scaled depending on the scope of the incident, he said, including anything from a house fire to a chemical spill. An evacuation or shelter-in-place order would go out through multiple channels, Kolakowski said, including social media, local news, the city’s mass notification system, and the city website. City agencies that would be involved in an evacuation conducted an emergency response drill with federal and state officials last summer.

Only Pennsylvania’s governor can call for an evacuation in the event of an emergency, Kolakowski said.

In a major incident, the city can reach residents directly through their phones via emergency alerts and can use a warning system through television and radio stations.

Though the former PES refinery in Philadelphia closed in 2019 after an explosion and fire, there are plenty of other petroleum-related industries operating in the region — all connected by rail, said Zerbo of the Clean Air Council.

Zerbo said that just south of Philadelphia, the Marcus Hook Industrial Complex, terminus of Sunoco’s Mariner East pipeline, and the Trainer Refinery, both in Delaware County, use existing networks of rail lines that crisscross the region.

For example, Energy Transfer says on its website that its Marcus Hook Terminal receives refined petroleum products through ships, pipelines, trucks, and rail. Other refining operations in Delaware City, Del., and Paulsboro also use rail networks. Those don’t include chemical companies also operating in the region, which Zerbo noted is much more densely populated than East Palestine.

Trains carrying vinyl chloride pass through Philadelphia, said Tracy Carluccio, deputy director of the Delaware Riverkeeper Network, as do trains carrying oil and related chemicals.

Carluccio and other environmental activists are also fighting against a plan to transport liquefied natural gas from Bradford County, Pa., to a $6.4 billion export terminal in Gibbstown, Gloucester County, along a route that would pass through Philadelphia. Natural gas is typically transported by pipeline, and activists are concerned about the consequences of trains filled with the flammable substance passing through densely populated areas.

“It’s a web of networks, these freight railways,” Carluccio said. “Particularly if you’re in Philadelphia because the city is so compact.”