Ontario, OR -

Cleanup and restoration crews are at work on the H.J. Heinz Co. frozen food factory in Ontario. Fire last month damaged it extensively.

Heinz spokesman Michael Mullen tells the Ontario Argus Observer the Dec. 21 fire started in the plant's packaging area, and Heinz is conducting an investigation into the cause.

Ontario Police Chief Mark Alexander has said foul play isn't suspected. Fire Chief Al Higinbotham says an early estimate of damage was $15 million to $20 million.

Mullen said the factory employs about 800 people, and it was closed for the holidays when the fire occurred.

The company placed ads to hire cleanup workers after the fire. It hasn't said when it would resume normal operations.