The Latest on a fire at U.S. Steel coke plant (all times local):

5:50 p.m.

Health authorities are threatening to shut down U.S. Steel's suburban Pittsburgh coke plant unless it comes into compliance with air emissions standards.

The Allegheny County Health Department issued an emergency order Monday after a fire at the steel producer's coke works in Clairton knocked out equipment used to remove toxic gases.

Health officials say U.S. Steel must submit a plan within 24 hours and achieve compliance with emissions limits for hydrogen sulfide and sulfur dioxide within 20 days.

The health department says air monitors have not detected elevated sulfur dioxide levels from the early-morning fire. Officials say residents should be aware of the potential for elevated levels of the gas but don't yet need to take precautions.

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Noon

Health officials in western Pennsylvania say a fire at U.S. Steel's Clairton Coke Works has shut down pollution control systems, and residents are being warned about possible elevated levels of sulfur dioxide.

The Allegheny County health department says fire in an electrical breaker panel shortly after 4:30 a.m. Monday shut down three control rooms, and two still down house equipment used to operate pollution controls, including desulfurization.

Officials say the elderly, parents of children and people with respiratory conditions should be aware that elevated levels of sulfur dioxide are possible.

U.S. Steel says it is taking mitigation steps such as replacing coke oven gas with natural gas and flaring while the damage is being repaired.

The same two control rooms were damaged in a $40 million Christmas Eve fire.