JAPAN'S CHERNOBYL: Stocks dropped Tuesday after Japan said the crisis at its crippled nuclear plant was as serious as the 1986 Chernobyl accident, though much less radiation has leaked.
ALCOA: Alcoa Inc. dropped 6 percent after the aluminum maker's first-quarter revenues fell short of expectations. Alcoa, one of 30 companies in the Dow average, is the first large company to report quarterly earnings.
THE INDEXES: The Dow Jones industrial average fell 117.53 points, or 0.9 percent, to close at 12,263.58. The S&P 500 index fell 10.30, or 0.8 percent, to 1,314.16. The Nasdaq fell 26.72, or 1 percent, to 2,744.79.