Toledo cut the evacuation zone around a leaking chemical tank to a half mile Wednesday, according to 13abc and ABC News. Officials also lifted an order for people to stay inside. The leak began late Tuesday at MC Tank Transport on Progress Avenue in north Toledo.

At first, everyone within 1 mile of the site had to leave, and people within 3 miles had to stay inside, ABC News reported. The city says the stay-inside order was lifted at 5 in the afternoon Wednesday.

The Ohio EPA named the chemical as glycidyl methacrylate. It "came from a 5,500-gallon tank because of an error that occurred when the material was being transferred," an agency spokesperson said, according to ABC News. 13abc reported the same account.

The US EPA said attempts to contain the release failed, so the chemical kept venting into the air, 13abc reported. City officials chose to let the reaction finish, saying that is the safest course. The city says the US EPA is running air checks around the edge of the zone.

By late Wednesday night, officials said concerns about an explosion had eased, WDIV reported. The tank's temperature was dropping, and less fog was coming from the site, it said. Officials had not said when people could go home.

The city says the chemical is "an irritant that can cause burning of the eyes, nose, mouth, and skin," ABC News reported. The health department said people with mild eye, throat or skin irritation should rinse the area and call their doctor. It said anyone with serious symptoms should go to an emergency room.

About 30 people had been treated at ProMedica hospitals in the Toledo area, a spokesperson said. Most were released, 13abc reported. ABC News, citing city officials and the health department, reported that at least 60 people were treated.

MC Tank Transport said its equipment was involved. "We understand the serious disruption this incident has caused to nearby residents and businesses," the company said, according to 13abc and ABC News.

What we know: The evacuation zone is a half mile, and officials say the risk has eased.
What we don't: When the release will end and when evacuated residents can go home.