"We are not capable of monitoring every inch of pipeline," Rose said.
The company keeps surveillance cameras on its pumping and booster stations, he said. The point of origin at Port Sutton and points of destination at fertilizer plants are behind locked gates.
As for fencing on the bridge: "For over 25 years we've had a pipeline there and never had an issue."
Rose said company employees drive the pipeline daily to look for problems.
In the next days and weeks the company will see whether it can do more, he said.
"We will go through the pipeline inch by inch and look at these areas and see if there is anything else we can do," Rose said.
The company's office manager, Nancy Taylor, said residents affected by the evacuation can seek reimbursement - "within reason."
Residents living within the evacuated zone can bring original receipts for food and lodging costs they incurred to the company's office at 5802 Hartford St. in Tampa. Hours are 7:30 a.m. to 4 p.m. The number to call is (813) 368-6122.
The company will review the receipts before dispersing payments, Taylor said.
"This company is not saying we're responsible for all this; we're just trying to be good neighbors," she said.
No decision has been made about reimbursing the businesses located within the evacuated zone that were closed during the emergency, Taylor said.
"It would be a difficult problem to prove how much money they would have lost, but it's not out of the question," she said. "We will definitely take a look at it."
Aside from the teenager, who had ammonia burns, no one was seriously injured. A handful of firefighters were treated for breathing problems Monday night, but they were released from the hospital by Tuesday morning.
It is too early to start tabulating the cost to the county, said Steve Valdez, county spokesman.
"It is going to be astronomical, and it is still mounting," he said.
Valdez said there are expenses from various county departments that responded, such as the sheriff's office, fire and rescue and public works.
"We've been in the mode of getting the bodies out and signing off on their overtime slips," he said. "An accounting will come later."
The Florida Department of Transportation also sent crews; first to check whether the bridge was sound and then to help keep traffic moving once it was closed. Kris Carson, FDOT spokeswoman, estimates her department's costs will be about $20,000 and that the state expects to be reimbursed by the pipeline's owner.
There was little financial cost to the Hillsborough County school district, said Linda Cobbe, a school district spokeswoman.
She said keeping Riverview Elementary School open as a shelter would be picked up by the American Red Cross and that the effect to the district's bus system was minimal.
The school was to reopen today for classes. Cobbe said no make-up days were expected because the district already had leeway in the school calendar. The two private schools, The Center Academy and Children's First Academy, also were to reopen today.
The 7.2 million gallons of water sprayed by firefighters over about 40 hours absorbed the ammonia and kept the toxic cloud in a protective envelope.
The Hillsborough Environmental Protection Commission got lab results Wednesday on water samples taken by scientists. The tests showed high levels of ammonia in the Alafia River about a half mile from the leak. That's not good, because ammonia contains nitrogen that can form algae blooms that deplete oxygen in the water.
The tests showed ammonia levels at between 2.1 to 3.1 milligrams per liter.