BY WALT “BUTCH” HENDRICK AND ANDREA ZAFERES
Public safety diving (PSD) has gone from being an “exotic” within a fire or police department to the norm. The size of the department, whether it is career or volunteer, or the amount of water in the jurisdiction doesn’t seem to be a criterion for establishing such a team. Despite the growing number of teams with decades of experience, the key question of the day, sadly, is the same as it was more than 20 years ago: What is the mission of a PSD team? What levels of training and maintenance are required for the operations the team intends to perform? “(See “Training and Maintenance Requirements for PSD Teams” on page 76.) How can we establish regional specialty dive teams to ensure reasonable response time for mass-casualty underwater emergencies? And, in the absence of that, what is the Go/No Go risk assessment for local teams during the immediate potential lifesaving part of the emergency?
The catastrophic collapse of the eight-lane I-35W bridge in Minneapolis, Minnesota, in August has made it more imperative than ever that these questions be answered. Such a collapse sends trucks, cars, trains, and human bodies into the water—in this case, the Mississippi River. In addition, twisted metal, cables, concrete, and other debris were scattered and piled on top of each other in every direction, some in the most tenuous ways.
This disaster gave new meaning to underwater search and rescue/recovery (US&R/R) or water search and rescue/recovery (WSAR/R). A bridge collapse water operation is similar to urban search and rescue/recovery, with added dynamics.
What are these dynamics? First, water adds pressure differentials1 that can cause lung overexpansion injuries, ear barotrauma, and other minor to potentially life-threatening gas-bubble injuries. There is a constant need for a source of breathing gas, which is used up more quickly as depth increases. The dynamics may likely include the following:
On the other hand, Underwater SAR/R teams are rarely similar. Within a single county, you can have teams that wear wetsuits and sport masks and octopuses who use handheld tether lines with buddy divers. Then there are other teams in vulcanized rubber drysuits, full face masks, quick-release pony bottles, harnesses with locking carabiners, and highly trained tenders who can run safe and effective solo tendered-directed dives. The former teams have a contingency plan of “send the backup diver down when the diver rapidly pulls the line and the backup diver feels around the needy diver to figure out what the problem is.” The latter teams have well-practiced blackwater contingency plans with diver-to-diver hand signals, a graduated system of help-line signals, and contingency equipment.
Victims submerged in vehicles usually have no air pockets in which to breathe or survive. To survive, submerged bridge collapse victims would have to be in a totally encapsulated airtight pressurized environment with a volume of air large enough to dilute the exhaled carbon dioxide to prevent suffocation.
Underwater. If there is no visibility because of turbulence or particles in the water, no amount of light can change it. You won’t even notice a 10,000-watt light. An infrared unit that can see in the dark but cannot light up the area can see only what it is looking at. Without light, every movement is a danger; actions can require three times the amount of planning and measuring before anything can be done. Unless they have been taught some tricks, divers may not even be able to monitor their own remaining gas supply. Visibility, or the lack of it, is typically our number-one issue.
Sonar can be used to help map out areas of debris that can be viewed by the sonar. But, sonar cannot read through concrete or other materials; it does not work like an X-ray machine reading through a body. So where a US&R/R technician can hold a light around a corner to peer into another space, sonar may be completely ineffective. The key difference is that US&R/R technicians see the collapse for themselves in live time. Divers only have access to sonar pictures when they are sitting on land or on a platform. They cannot access these visuals while diving.
Underwater. Currents are a major issue. First, divers should dive into water with currents greater than one-half knot in a downstream manner, since currents greater than this make it very difficult to move divers back and forth parallel to shore.
The accuracy of the search can be seriously compromised, and divers can become overexerted and have far greater air consumption rates. Most importantly though, what is the contingency plan for performing an effective rescue of your own when diving from shore in currents greater than one-half knot?
In moving water such as urban rivers, there is the constant threat of surface and subsurface moving debris such as logs, couches, and tires. They can injure divers. If a diver becomes trapped by such debris, the force pushing against the diver can be increased by the additional surface area of the item that is also affected by the current.
The risk of a diver’s becoming entrapped against debris by current goes up when the amount of debris or the current increases. Bridge collapses definitely increase the amount of debris and number of obstructions, which in themselves can increase currents. So it is a double risk.
The catastrophic collapse of the eight-lane I-35W bridge in Minneapolis, Minnesota, in August has made it more imperative than ever that these questions be answered. Such a collapse sends trucks, cars, trains, and human bodies into the water—in this case, the Mississippi River. In addition, twisted metal, cables, concrete, and other debris were scattered and piled on top of each other in every direction, some in the most tenuous ways.
 Click here to enlarge image |
This disaster gave new meaning to underwater search and rescue/recovery (US&R/R) or water search and rescue/recovery (WSAR/R). A bridge collapse water operation is similar to urban search and rescue/recovery, with added dynamics.
What are these dynamics? First, water adds pressure differentials1 that can cause lung overexpansion injuries, ear barotrauma, and other minor to potentially life-threatening gas-bubble injuries. There is a constant need for a source of breathing gas, which is used up more quickly as depth increases. The dynamics may likely include the following:
- Zero visibility and even blackwater. Not only will the diver not be able to visualize the debris, but the debris may be sharp, hanging tenuously, or ending in seriously confined spaces. The divers would require highly trained tenders to continuously guide and monitor them. Just as the divers cannot see, the tenders also cannot see the divers unless they are using specific types of very expensive sonar, which may not work when inside the debris.
- Currents.
- Floating and hidden hazmat problems in which the divers are immersed.
- The need for properly anchored operational platforms, such as boats or floating barges.
- Short search times (a maximum of 15 to 25 minutes) because of air management, diver and tender concentration capabilities, cold stress, loss of hand dexterity from heat loss, dehydration, diver rotation, and other issues.
- Aquatic animal concerns such as water moccasins, alligators, snapping turtles, and less-threatening critters such as eels and fish that bump you in the blackness.
UNDERWATER SAR/R VS. US&R/R TEAMS
Let’s examine some of the basic ways Underwater SAR/R teams differ from US&R/R teams.Uniformity in Training
US&R/R teams can come from all over the country and be trained in similar techniques and operations. Training facilities around the world, like Reykjavik, Iceland, teach procedures similar to those taught in the collapse school in the Calgary Fire Department Training Academy in Alberta, Canada. US&R/R teams have a trained, unified command structure and understand safety procedures and how to use the proper equipment for the job at hand. They have trained backup teams.On the other hand, Underwater SAR/R teams are rarely similar. Within a single county, you can have teams that wear wetsuits and sport masks and octopuses who use handheld tether lines with buddy divers. Then there are other teams in vulcanized rubber drysuits, full face masks, quick-release pony bottles, harnesses with locking carabiners, and highly trained tenders who can run safe and effective solo tendered-directed dives. The former teams have a contingency plan of “send the backup diver down when the diver rapidly pulls the line and the backup diver feels around the needy diver to figure out what the problem is.” The latter teams have well-practiced blackwater contingency plans with diver-to-diver hand signals, a graduated system of help-line signals, and contingency equipment.
 (6) Divers need to learn how to feel debris underwater to help prevent and manage entrapments and entanglements and move debris to access bodies. Click here to enlarge image |
Federal and State Regulations
Where do the state or federal Occupational Safety and Health Administration come into play in relation to PSD teams? Are they still exempt when it comes to confined-space operations, which bridge collapse dives can be? Are they exempt when the job requires commercial or military diving capabilities by divers and tenders who have hundreds or thousands of hours of experience instead of PSD divers with fewer than 50 to 100 dives?What Are the Benefits?
In US&R/R, victims have been saved after days or even weeks (up to 16 days) of entrapment, which is very different from Underwater SAR/R, where the only people who can be saved are those on the surface or, in extremely rare circumstances, in a location accessible to divers who can reach them while they are still viable.Victims submerged in vehicles usually have no air pockets in which to breathe or survive. To survive, submerged bridge collapse victims would have to be in a totally encapsulated airtight pressurized environment with a volume of air large enough to dilute the exhaled carbon dioxide to prevent suffocation.
Visibility
On land. Once the dust has settled, artificial lighting can be introduced in any number of ways, anything from handheld to stationary halogen. Practically every fire and rescue company in our country carries portable high-intensity lighting. Thousands of feet of cable can be run to support a single light source or a passage for access. Once lighting has been established, rescuers can see and can focus on specific items of danger. Rescuers can plan the reaction of an action—how to support an item to remove another item. Visibility allows for planned movements, thereby reducing the extent of the unknown danger.Underwater. If there is no visibility because of turbulence or particles in the water, no amount of light can change it. You won’t even notice a 10,000-watt light. An infrared unit that can see in the dark but cannot light up the area can see only what it is looking at. Without light, every movement is a danger; actions can require three times the amount of planning and measuring before anything can be done. Unless they have been taught some tricks, divers may not even be able to monitor their own remaining gas supply. Visibility, or the lack of it, is typically our number-one issue.
Sonar can be used to help map out areas of debris that can be viewed by the sonar. But, sonar cannot read through concrete or other materials; it does not work like an X-ray machine reading through a body. So where a US&R/R technician can hold a light around a corner to peer into another space, sonar may be completely ineffective. The key difference is that US&R/R technicians see the collapse for themselves in live time. Divers only have access to sonar pictures when they are sitting on land or on a platform. They cannot access these visuals while diving.
Currents
On land. Usually, there are no currents in US&R/R. The definition of a land scene is that there is no water in the scene. Once part or all of the collapse is submerged, that location becomes an underwater scene. The Minneapolis bridge collapse was no longer a land scene. Only divers could enter the underwater part of that scene, and currents existed only in the water.Underwater. Currents are a major issue. First, divers should dive into water with currents greater than one-half knot in a downstream manner, since currents greater than this make it very difficult to move divers back and forth parallel to shore.
The accuracy of the search can be seriously compromised, and divers can become overexerted and have far greater air consumption rates. Most importantly though, what is the contingency plan for performing an effective rescue of your own when diving from shore in currents greater than one-half knot?
In moving water such as urban rivers, there is the constant threat of surface and subsurface moving debris such as logs, couches, and tires. They can injure divers. If a diver becomes trapped by such debris, the force pushing against the diver can be increased by the additional surface area of the item that is also affected by the current.
The risk of a diver’s becoming entrapped against debris by current goes up when the amount of debris or the current increases. Bridge collapses definitely increase the amount of debris and number of obstructions, which in themselves can increase currents. So it is a double risk.
