Burruel and the 4,000 members of his Cleveland Iron Workers Local 17 pension plan are the canaries in the coal mine as far as pension cutbacks go. At least 50 Midwestern pension plans — mostly the kind jointly administered by trustees for a labor union and a group of employers — are in this decrepit condition. Several plan sponsors have already applied to the Treasury Department to cut back retirees’ allotments. . . .When people such as Burruel retired, fewer workers in fewer jobs were available to contribute to the pension plan. That created a lopsided and unsustainable equation. Low interest rates made matters worse. The area economy was yet another factor. Although things improved economically on both coasts, the Ohio region where Larry and his fellow workers lived remained depressed. When companies there failed, they couldn’t continue to pay pension benefits and, in some instances, declared bankruptcy.