The Federal Reserve's report on Tuesday showed production at the nation's factories, mines and utilities has fallen for seven straight months. Output also turned out to be a bit weaker - a 0.7 percent decline- in April than the Fed initially reported.
The 1.1 percent drop registered in May was the deepest since a 1.8 percent plunge in March. Economists expected a decline of 0.9 percent last month.
The recession has crimped demand in the U.S. for all kinds of manufactured goods, especially those related to the housing sector.
Factories also are coping with less demand from foreign buyers struggling with their own economic problems.
Plant shutdowns at Chrysler LLC and General Motors Corp., which recently filed for bankruptcy protection, also weighed on industrial production last month and probably will continue to do so through part of the summer, economists say.
Against that backdrop, industrial companies idled more of their plants and equipment. The overall operating rate fell to 68.3 percent in May, a record low dating to 1967. The previous low was set in April, when operating capacity dropped to a revised reading of 69, slightly weaker than first reported.
The pullbacks factored into a drop in the operating rate at factories, which fell to 65 percent in May, the lowest on records dating to 1948. The previous low was set in April.
Production of appliances, furniture and carpeting fell 1.1 percent, partly reversing a 1.5 percent increase in April. Production of home electronics declined 1.9 percent, following a 1.4 percent decline in the previous month.