Nov 13 (Reuters) - An investigation was underway in

Kentucky on Wednesday into what caused an explosion that leveled

a Louisville factory, killing two people and injuring several

others.

The blast occurred at about 3 p.m. EST (2000 GMT) on Tuesday

at a factory owned by Givaudan that makes colors and

aromas for the food and beverage industries, according to the

company's website.

Two people were killed in the explosion, the company said on

Wednesday.

Twelve people were taken to hospitals with various injuries,

Louisville Mayor Craig Greenberg said in a statement. The

injuries ranged from minor to critical and life-threatening.

The Louisville Fire Department was leading the investigation

and a federal reconstruction team from the Bureau of Alcohol

Tobacco, Firearms and Explosives will help determine the cause

of the incident, Greenberg said.

The blast was heard throughout the city and blew out windows

in nearby buildings, local news outlets reported.

City officials said air quality testing was being done at

the site, but as yet there was no indication of any danger.

A shelter-in-place order was issued for anyone within a

one-mile (1.6-km) radius of the blast. That was lifted about 90

minutes after the explosion, according to the Louisville Metro

Emergency Services.