GOODYEAR TIRE & RUBBER CO. and the United Rubber Workers reached tentative agreement on a three-year contract covering 12,000 workers in eight states. . . . AN EXPLOSION in a fireworks factory in eastern China's Henan province killed 17 people and injured 10. . . . AN EARTHQUAKE shook three towns in Soviet Buryatia near Lake Baikal Monday, the Tass news agency said.