Congressional investigators say the government has failed to inspect virtually all of the chemical facilities considered a high risk for a terrorist attack, and has underestimated the threat to densely populated cities. A year-long investigation by Republican staff on the Senate Homeland Security Committee shows inspection delays, government errors in risk assessment and industry loopholes in a 595 million dollar terrorism prevention program. The report says the Department of Homeland Security failed to conduct security inspections on nearly 4 thousand chemical facilities, or 99 percent of those deemed higher risk. Roughly half of the higher-risk facilities are in Ohio and nine other states.