The owner of a Louisiana ethylene and propylene plant faces a $99,000 fine for alleged workplace safety violations after a June explosion that killed two workers and injured scores of others. OSHA proposed the penalty earlier this month when it cited Williams Olefins LLC for six alleged violations of federal standards for process safety management. OSHA says one of those alleged violations was willful because Williams Olefins failed to develop written procedures, as required, for putting idle pressure vessels into service. Tulsa-based Williams Partners LP, which owns Williams Olefins, says it is reviewing OSHA’s findings and is committed to enhancing safety performance. The company, which was expanding its Geismar, La., facility when the explosion occurred, is rebuilding and plans to complete the expansion by April 2014.