Half of the state's population — 1 million residents — could be harmed by toxic gas exposure were terrorists to attack a Utah chemical storage facility, the Congressional Research Service reports.

The research service doesn't mention the Utah plant by name in its assessment of the up to 112 facilities nationwide storing dangerous chemicals that if attacked could harm 1 million or more people. The analysis was prepared for Rep. Edward Markey, D-Mass.

Chemical storage plants are especially tempting terrorist targets because they generally are not guarded well, Markey said. "There are nightclubs in New York City that are harder to get into than some of our chemical plants," he said.

However, Verdi White, director of the Utah Division of Homeland Security, described the plans in place to protect critical infrastructure as "pretty good." He says plant officials and officials throughout the state have worked hard to help protect against attack and to handle any release of toxic compounds should that ever occur.

Markey asked the CRS to analyze risk-management plans and maps that plants provide to the Environmental Protection Agency plotting potential dangers to people downwind in a "worst-case scenario" release of toxic substances.

The CRS said one plant in Utah could threaten 1 million or more people if attacked; five other Utah sites could threaten 100,000 to 999,999 people each; 11 others could hurt 10,000 to 99,999 people; and 18 to 20 could hurt 1,000 to 9,999 people.

Nationally, the CRS reported that 108 to 112 plants could threaten 1 million or more people; 435 to 493 could threaten 100,000 to 999,999; 1,835 to 2,120 could threaten 10,000 to 99,999 each; and 3,999 to 4,828 plants could threaten 1,000 to 9,999 each.

Although the CRS did not identify the plants by name, White said Utah officials have a good idea which of its plants were likely included in the statistics. He declined to identify them for security reasons.

"Based on the ones that we have knowledge of, we feel really good about the security of them," White said.

"Plants have a proprietary interest to stay in business and to take the (security) steps needed to ensure that they will," he said.

White said local police and other officials also have done a good job of patrolling and keeping a close eye on key plants. Utah established a system during the 2002 Olympics — which it still maintains — for local governments to share information about "bad guys who might be interested in them, or watching them," White said.

State and local government also regularly have training and practices on how to handle the release of toxic substances. That came in handy in March, when 8,000 people were evacuated in South Salt Lake and thousands more diverted from freeways when a rail tanker car began leaking a mixture of acids.