Bridgestone Americas will invest an additional $74 million through next year to expand its Firestone tire factory in Des Moines (Rubber World). The Des Moines Register reported the investment is in addition to Bridgestone’s $77 million project at the plant, which was announced in March 2010. The plant has added about 250 workers in the past two years, bringing the total to nearly 1,700 people. The plant makes tires for the agricultural, forestry and construction equipment markets.