The nation's manufacturers continue to struggle with higher wholesale prices, which rose by 0.2 percent last month to a 17-year high, the Labor Department reported this week.
Despite the increases, which followed gains of 1.1 percent in March and 0.3 percent in February, food prices remained flat and energy prices declined in April, the report said.
Excluding food and energy, so-called core producer prices rose by 0.4 percent, the sharpest increase since mid 1991.
In the past year, wholesale prices have jumped by 6.5 percent, including a surge in prices for intermediate and crude goods for production. Since September, the Federal Reserve has slashed interest rates by 3.25 percent, amid turmoil in the housing and credit markets and growing fears of widespread inflation.