Firefighters were still battling small fires Friday, after working through the night to put out the main blaze, state media reported.

Drone footage from the country’s emergency management ministry shows an industrial area outside Yancheng city in Jiangsu province covered in firefighting foam, with storage tanks turned to twisted metals and charred factory buildings with roofs torn open.

Local authorities said earlier that dozens of fire trucks and hundreds of firefighters rushed to the scene after the blast was reported around 2 p.m. Thursday.

 The explosion was powerful enough for the seismological bureau to detect a small earthquake in the area, according to state media.

National broadcaster CCTV aired dramatic surveillance and cell phone videos of windows blown out in nearby buildings at the time of blast, with witnesses telling reporters the impact could be felt as far as 5 kilometers (3 miles) away and others saying they suffered cuts from broken glass.

Several schools are situated near to the chemical plant, Tianjiayi, including a kindergarten less than a mile away, state media reported, prompting concern and anger on Chinese social media.

State media reported the chemical that caused the explosion was benzene, a highly flammable and toxic compound classified as a carcinogen, adding that the pesticide factory failed a government safety inspection last year.

Local environmental officials, who set up monitoring devices throughout the industrial park and nearby areas after the blast, said Thursday that heavy wind had created favorable condition for toxic air to dissipate.

The authorities have detained “relevant personnel connected to the accident,” according to state media.

President Xi Jinping, on a state visit to Italy, urged rescuers to keep working and ordered officials draw immediate lessons from the accident.

In August 2015, a series of chemical explosions at a container storage facility in the northern city of Tianjin killed more than 160 people and injured nearly 800 others.

A months-long government investigation found an overheated container of highly flammable dry nitrocellulose caused the initial blast, with ensuing fires burning uncontrolled for days.

The authorities eventually arrested and sentenced almost 50 government officials as well as company executives and employees for their roles in the fatal accident, blaming lax safety standard and corruption.