It took 18 hours to unload explosives from a truck that crashed Wednesday on the Springfield interchange because authorities undertook painstaking research about how to handle the equivalent of a 17-ton bomb. The resulting commuting nightmare was exacerbated because officials had to scramble to make a plan for detouring traffic in such an emergency.

Once county and state officials decided they'd have to close three of the area's most congested interstates while they removed 34,000 pounds of explosive powder, it took them two hours to plan and deploy more than 70 officers to help direct traffic. That prompted some Fairfax County officials yesterday to criticize state authorities for a lack of preparedness.

The process of removing the potentially lethal load was so arduous, state and local emergency officials said yesterday, that in retrospect, both the morning rush hour and the evening commute were doomed. The flatbed truck that overturned on a northbound exit ramp to Interstate 95 was carrying enough powder to produce a blast seven times stronger than the bomb that devastated the federal building in Oklahoma City.

But as dawn broke Wednesday, few officials had imagined it would require until nightfall to remove the cargo.

For nearly six hours after the 4 a.m. incident, police and fire officials tried to research the cargo, which had been manufactured in Brazil and changed hands several times before being loaded on the flatbed truck in Newport News, Va., and how to deal with it.

More challenging was finding experts versed in handling explosives that might have been strewn about the inside of the damaged shipping container.

"Identifying what we had was not as difficult as the task of finding out what to do with it under these circumstances," said Michael Neuhard, Fairfax County fire battalion chief. "People are used to handling the material in controlled environments."

Local officials said they contacted demolition experts at Fort Belvoir, the New Mexico Institute of Mining and Technology and the Institute of Makers of Explosives, as well as the trucking and import companies. The manufacturer of the material could not be reached in Brazil, so similar outfits were contacted in the United States.

Although a Bureau of Alcohol, Tobacco and Firearms agent had been on the scene since morning, bureau explosives teams were not requested until 2 p.m., said Brad Earman, a special agent in the Washington field division. He said the bureau plans to review whether its help should have been requested sooner.

Officials also trolled the Internet looking for companies capable of clearing boxes of black power that potentially had been damaged and were certainly heating up in the sunshine.

Advice varied. Several demolition experts recommended that all buildings and roads be evacuated within 7,900 feet of the wreck because of the potential size of a blast and range of flying debris. That could have entailed emptying at least 2,000 homes. But Neuhard said a review of the local topography and the location of the crash required that the evacuation be limited to 2,500 feet -- or about 100 homes.

With the cost of a wrong step so grave that workers even went shoeless and donned static-free cotton clothing to avoid sparks, county officials waited until they had reviewed each option and marshaled government and private forces. Crisis-response teams, including those from three private companies, were ready to begin their mission by 2 p.m. but had to wait until 3:30 while police closed the surrounding highways and detoured the traffic, officials said.

Some Fairfax County officials suggested that the absence of a recent emergency detour plan for closing both the Capital Beltway and Shirley Highway had needlessly delayed things. Redeploying 70 officers to direct traffic could have added two hours, said Fairfax County Supervisor T. Dana Kauffman (D-Lee), who represents the Springfield area. But even if that time had been saved, it would not have been enough to complete the work before rush hour.

Lucy Caldwell, a Virginia State Police spokeswoman, added that any traffic management plan would have been hard-pressed to anticipate the extraordinary circumstances surrounding the crash. "No plan can encompass or fathom something as major as this involving all these roads," she said.

State police continued their investigation into the crash yesterday.

Driver Juanita I. Kirk, with Tri-State Motor Transit Inc., told police that she had heard a popping noise as she traveled on the exit ramp before her rig overturned. Kirk was charged Wednesday with reckless driving. No further charges have been filed against her, police said.

Kirk, 41, of Phoenix, has held a commercial driver's license in Arizona since 1997. Her record there is clean except for a citation from out of state that was filed May 31, according to a spokeswoman for the Arizona Department of Motor Vehicles, who said the records do not yet specify what the violation was.

From 1990 to 1997, Kirk held an Oregon commercial license. State records show that Kirk was required to complete a driver's safety class in 1995 because she received six traffic tickets, some for speeding and some for other violations, over a year's period but that her license was never suspended or revoked.