Martin Marietta Corp. has agreed to pay $13 million to settle an age discrimination lawsuit filed by the EEOC on behalf of thousands of former employees who were laid off. The company also agreed to rehire 450 eligible employees who took part in the lawsuit and to make future layoff decisions under EEOC scrutiny over the next five years. Reductions in force will be scheduled only after the company conducts a statistical analysis to determine the impact on workers over 40 and records the reasons for each layoff.