A train derailment and chemical spill forced the evacuation of about 400 homes Tuesday night in Willard.
City Manager Brian Humphress said about 26,000 gallons of flammable liquid was spilled and it could take some time to clean it all up.
Willard High School has been set up as a shelter.
The incident occurred in the Willard rail yard near the underpasses on North Main Street. The chemical, styrene monomer, is highly flammable.
The evacuation area is Washburn Road to the west, Townline Road/Niver Road to the north, Second Street to the northeast, Myrtle Avenue to the southeast and Tiffin to the south.
Willard public safety and CSX cleanup crews are on the scene.
Willard officials have stated as soon as they reliably know residents can return to the area, they will send out a notification through the Everbridge alert system.
Residents of the evacuation zone who have pets still located in their homes are asked to contact the Willard police department.
Attempts are going to be made to remove the animals to a safe location where they can be housed and fed. Call the police or city to coordinate this, Willard officials said.
Also, those residents who need to obtain their medications from their homes should also contact the police department.
"Due to the concerns for public safety, the cleanup effort by CSX is going slower than originally anticipated," Willard officials stated on the city's Twitter feed.
"Therefore, the evacuation zone will remain in effect until further notice," officials added.
"There is a possibility that residents of part of the area may not be able to return to their home for a couple of days."
"CSX and state officials are constantly monitoring the situation and the cleanup, including the draining of the damage tanker, is under way," officials said. "However, the flammability of the styrene monomer is such that caution must be utilized to protect the public safety.
"Therefore, until soil and air monitoring indicates it is safe for residents to return to their homes, we (ask) everyone to be patient," officials added. "We hope that the initial testing will be completed within a few hours. At that time, we will pass on when we expect residents may return.
"The goal of everyone involved is to return residents to their home as quickly as safety concerns will allow," officials said on Twitter.