Story highlights Twenty-four people killed in Mexican chemical plant explosion, officials say

Fire creates huge plumes of toxic smoke, prompting evacuations and school closures

It is the latest fatal incident at facilities linked to Mexican state oil company

(CNN) The death toll from a huge explosion at a Mexican petrochemical plant that forced the evacuation of surrounding neighborhoods has risen to 24, authorities said.

Photos: Explosion rocks Mexico chemical plant Smoke billows into the sky after a deadly explosion at a petrochemical plant in Coatzacoalcos, Mexico, on Wednesday, April 20. Hide Caption 1 of 9 Photos: Explosion rocks Mexico chemical plant Smoke rises from the plant. Hide Caption 2 of 9 Photos: Explosion rocks Mexico chemical plant Relatives wait outside a hospital after the explosion. Hide Caption 3 of 9 Photos: Explosion rocks Mexico chemical plant A worker receives help while being admitted to the hospital in Coatzacoalcos. Hide Caption 4 of 9 Photos: Explosion rocks Mexico chemical plant The explosion creates smoke and toxic fumes. Hide Caption 5 of 9 Photos: Explosion rocks Mexico chemical plant A security guard protects a store damaged by shock waves from the explosion. Hide Caption 6 of 9 Photos: Explosion rocks Mexico chemical plant Relatives of missing plant workers demand news about loved ones outside a hospital in Coatzacoalcos. Hide Caption 7 of 9 Photos: Explosion rocks Mexico chemical plant A woman places a list of missing workers outside the hospital. Hide Caption 8 of 9 Photos: Explosion rocks Mexico chemical plant Relatives of missing workers pray as they wait for news. Hide Caption 9 of 9

Wednesday's explosion at the Petroquimica Mexicana de Vinilo facility in the southern state of Veracruz sent large plumes of dark smoke and toxic fumes across the region.

Javier Duarte, governor of the state of Veracruz, told CNN affiliate Televisa that the blast was felt about 10 kilometers (six miles) away. Emergency protocols were put in place, with surrounding municipalities evacuated and schools closed in others, officials said.

PMV is a joint venture between Mexican petrochemicals consortium Mexichem and state oil firm Pemex.

A government Twitter account showed photos of plant workers being evacuated from the facility in a convoy.

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