DuPont Co., the nation’s largest chemical company,...

DuPont Co., the nation’s largest chemical company, reported a 30% gain in first-quarter earnings, reflecting strong gains in its key businesses as well as cost cutting.

DuPont reported earnings for the first three months of $642 million, or 94 cents per share, compared to $493 million, or 73 cents per share, in the first quarter of 1993.

Excluding a $32-million non-recurring gain from the exchange of North Sea petroleum properties, the Wilmington, Del.-based company’s first-quarter 1994 net income was up 39%.