Faced with the possibility of mass absences as swine flu runs its course, major companies are struggling to draw up contingency plans.

Businesses are having a hard time with the specifics, though, as they have never encountered a major flu outbreak.

Yokogawa Bridge Holdings Corp., a major bridge construction company, held a heated discussion at its headquarters last month about how many weeks it would have to anticipate its employees will remain absent if 30 percent to 40 percent of them come down with the new H1N1 flu.