*

Two people, including missing employee, confirmed dead

*

Cause of the explosion is not known

*

Clairton Coke Works is the largest coke manufacturing

facility

in the US

*

Nippon Steel ( NISTF ) recently acquired U.S. Steel for $14.9

billion

(Rewrites first paragraph, adds company statement in paragraph

4)

By Rich McKay and Julia Harte

Aug 11 (Reuters) - Multiple explosions on Monday at a

U.S. Steel plant near Pittsburgh killed two people and injured

10 others, according to the company and local authorities.

The blasts at the Clairton Coke Works - part of a sprawling

industrial complex along the Monongahela River - took place just

before 11 a.m. ET (1500 GMT). Firefighters battled flames and

heavy smoke that billowed out of the plant, which is owned by

U.S. Steel, a subsidiary of Nippon Steel ( NISTF ).

Initially, two people were reported missing. One person was

found and transported to a local hospital, said Allegheny County

Police Assistant Superintendent Victor Joseph at an afternoon

briefing.

The other individual, who had been missing, was found

deceased following an extensive search and rescue effort, U.S.

Steel said in an emailed statement to Reuters late on Monday.

There was no word yet on a possible cause of the explosion.

The probe into the explosion would be "a time-consuming

technical investigation," Joseph said.

David Burritt, president and chief executive officer of U.S.

Steel, said in a statement that the company was working with

local authorities to discover the cause.

Pennsylvania Governor Josh Shapiro posted on X that there

were multiple explosions at the plant and that his

administration was in touch with local officials.

"The scene is still active, and folks nearby should follow

the direction of local authorities," he wrote at the time the

employee was missing.

The severity of the injuries was not known, but news

accounts said that several people were taken to hospital burn

units.

Clairton Mayor Rich Lattanzi said it was a horrible day for

the city, about 20 miles (32 km) south of Pittsburgh, long known

as America's Steel City.

U.S. Steel has produced steel in the area since the late

19th century, but in recent decades, the industry has been in

decline, leading to plant closures and restructurings.

In June, Nippon Steel ( NISTF ), Japan's biggest steelmaker, closed

its $14.9 billion acquisition of U.S. Steel after an 18-month

struggle to obtain U.S. government approval for the deal, which

faced scrutiny due to national security concerns.

While air quality monitors did not detect a dangerous rise

in sulfur dioxide after Monday's explosions, residents within 1

mile of the plant were advised to remain indoors, close windows

and doors, set HVAC systems to recirculate, and avoid activities

that draw in outside air, said Allegheny County Executive Sara

Innamorato at the briefing.

The Clairton Coke Works is the largest coke manufacturing

facility in the United States, employing about 1,300 workers.

It operates 10 coke oven batteries, which produce about 4.3

million tons of coke a year.

Coke is produced by heating coal at high temperatures. It is

used in blast furnaces as part of the process of making steel.