Raw steel production in the country's Great Lakes region plunged to 685,000 tons in the week that ended Saturday, according to an American Iron and Steel Institute estimate.
Production fell by about 23,000 tons, or about 3.2 percent, from the week prior, after three straight weeks of big gains. Most of the raw steel production in the Great Lakes region takes place in Indiana and the Chicago area.
Production in the Southern District was estimated at 583,000 tons, up from 574,000 tons a week earlier.
Total domestic raw steel production last week was about 1.82 million tons, which was down from about 1.83 million tons a week earlier.
U.S. steel mills had a capacity utilization rate of 75.9 percent last week, down from 76.3 percent a week earlier. The capacity utilization rate had been 71.7 percent at the same time last year.
So far this year, domestic steel producers have had a capacity utilization rate of 77.1 percent, which is up from 75.2 percent during the same period in 2012.
Domestic mills have produced an estimated 92.3 million tons of steel this year, down 1.4 percent from the same period last year. The mills had made about 93.6 million tons of steel by Dec. 14, 2012.
In September, steel exports declined by 10.9 percent., as compared to August, according to the American Institute for International Steel. Exports are down by 8.1 percent so far this year.
"Steel exports throughout 2013 for most months have reflected a weaker international market, and so the disappointing results for September might have been a continuation of that trend, or affected to some degree by the government shutdown," said Richard Chriss, executive director of the American Institute of International Steel. "International economic conditions indicate that the record year for American exports of steel in 2012 is not likely to be bested in 2013."