The Illinois Department of Public Health declined to investigate 85% of the 560 hospital complaints it received last year, even when the reports alleged violations such as patient abuse and inadequate infection control, records show. Some allegations of serious harm or death were not pursued even though federal law requires that such claims be investigated within 48 hours. "These are serious complaints," said Lisa McGiffert, director of the national Consumers Union Safe Patient Project. "If the regulatory system is collecting these complaints and not responding, that is a massive failure of oversight." Complaints can reveal crucial systemic problems, experts say. And when it finds violations, the state can order hospitals to make corrections.