April 2, 1986

Stock prices plunged yesterday, with prices hurt by sell programs that began after Prime Computer projected a 25 percent drop in first-quarter earnings. The Dow Jones industrial average was off about 35 points in late afternoon and ended with a drop of 28.50 points at 1,790.11. The decline was the biggest since March 21, when the Dow fell 35.68, to 1,768.56.

''We will impose the full penalties of the law on those who blatantly or repeatedly violate safeguards necessary to protect American workers.'' - Labor Secretary Bill Brock on proposed fine against the Union Carbide Corporation. [ A1:3. ]

Oil prices swung wildly yesterday, plunging below $10 a barrel in the world oil market before rebounding on word that the United States would press Saudi Arabia to help stabilize the market. Prices for May delivery of West Texas Intermediate, the main grade of United States crude oil and an important market indicator, dropped as low as $9.75 per 42-gallon barrel on the New York Mercantile Exchange, compared with Monday's price of $10.42. Prices for West Texas Intermediate had not been so low since the mid-1970's. The price slide spilled over to Europe, where Britain's benchmark Brent crude oil from the North Sea fell as much as $1.90 in the spot market, to $9.70 a barrel, its lowest level since 1973.

President Reagan has approved sweeping changes for the Pentagon, including strengthening the role of the Chairman of the Joint Chiefs of Staff and creating a post to oversee the development and production of weapons, White House officials said today. The changes were recommended by a blue-ribbon commission Mr. Reagan created amid reports of fraud and waste within the Defense Department and a continuing debate over the department's command apparatus. White House officials in Washington said Mr. Reagan's decision would be announced here Wednesday or Thursday, even as he faces an uphill fight in Congress for his Pentagon budget, which includes an increase of 8 percent on top of an increase to make up for inflation. [ Page B12. ] The officials said Mr. Reagan's decision reflected his commitment to curbing waste and abuse within the Pentagon and to weeding out inefficiency.

Two American tourists from Dayton, Ohio, had just gotten out of the Paris metro and were strolling up the Avenue des Champs Elysees on the evening of March 20 when a bomb, later linked to an Arab prisoner group, exploded in a shopping gallery. It killed two passers-by and injured 28 others. Shaken, the two women nevertheless kept their dinner plans at a nearby restaurant on the Champs-Elysees, Restaurant L'Alsace, but watched the racing ambulances and police cars with growing apprehension. ''When we touch down in America, I'll heave a sigh of relief,'' said Mrs. Robert Herbruck. ''We had planned on coming, so we came. But I wouldn't go a foot farther than we have.''