Washington ? The government’s emergency management chief, disturbed by the failure of critical facilities like water and sewage treatment plants during this month’s widespread power blackout, said Monday he was looking into ways to prevent a repetition.

Mike Brown, director of the Federal Emergency Management Agency, said in an interview with The Associated Press he has initiated a national inventory of backup systems and vulnerabilities in the country’s infrastructure to prevent future failures.

The nation’s worst blackout occurred nearly two weeks ago after cascading power failures darkened parts of eight states, from Ohio to New York. Water systems in Detroit and Cleveland were unable to handle the drop in power, and residents were asked to boil water while engineers made sure the system was free of contamination.

“It is unacceptable to me that water treatment plants, for example, don’t have backup power or that water treatment plants are susceptible to that kind of outage,” Brown said, adding he was surprised to learn many Midwest water and sewage facilities could not maintain a clean water supply.

“While I don’t want to give a road map to terrorists of how to disrupt our economy and how to disrupt our lifestyle, I think we saw in Detroit and other places that that is a vulnerability we need to address.”

Brown, who was sworn in as head of FEMA and an undersecretary of the Department of Homeland Security in April, did not say how long it would take to complete the massive fact-finding effort, which will also look at other possible weaknesses besides water treatment.

He said FEMA also was conducting an internal review to determine how many of its own emergency response facilities lack backup power.

The “silver lining in the blackout,” Brown said, was watching so many citizens rush to buy flashlights, batteries, and emergency supplies. The agency has been encouraging people to do that in preparation for terrorism or disaster.

Over the weekend, President Bush authorized up to $5 million in FEMA aid for New York state in the wake of the blackout.

On Monday, Brown left the door open to more federal aid to New York and other states with economic losses from the blackout. “Based solely on what I’ve read in the newspapers, New York may go over the $5 million cap,” in emergency assistance.