The implosion has been postponed a week because of problems with project materials. Caltrans says the plastic coating wasn't uniform enough on the 20,000 pounds of explosives, so they put off the project.
The agency spent a long time Tuesday morning detailing what to expect on demolition day.
The implosion taking place next Saturday will likely be less spectacular than others because it will take place underwater.
"I don't want to call it an experiment. Because an experiment suggests you don't know what's going to happen. I would call it a test," Chief Bay Bridge Engineer Dr. Brian Maroney said.
The target is a piling from the old Bay Bridge that extends 275 feet beneath the surface into the bay mud itself.
Maroney got fairly animated on the subject. "We see that we have a cellular structure that goes down hundreds of feet, so let's place that material right there, efficiently, and entomb it below the mud line, where it is not a hazard to anybody," he said.
Though nearby birds, sea mammals and especially fish may not see it that way.
It is a foregone educated estimation that 1,700 Longfish Smelt, plus other species, will perish in the shock wave.
It is a calculated decision that has the blessing of the San Francisco Bay Conservation and Development Commission, among others.
"We at BCDC and at the resources agency know that species will be killed. Individual fish will be killed. The question that our commissioners really had to weigh is whether it is preferable to have six seconds worth of impact versus 48 months of impact," BCDC spokesperson Larry Goldzband said.
That's how long it would take to remove the pier by more traditional means.
If this works, Caltrans may use the same technique to remove all the other old bridge piers as well.
For the record, there are 20 of them.