Stopping intruders can be a sticky mess: Joint non-lethal program office funds development of Mobility Denial System.

• Author: Tiron, Roxana
• Position: Sticky gel

In the future, U.S. military peacekeepers and law enforcement authorities may use a novel sticky gel to prevent trespassers or troublemakers from entering a building or to stop a run-away vehicle without having to use lethal force.

The gel is part of a crowd-control anti-traction technology currently in development, known as the Mobility Denial System.

MDS is supposed to serve as a deterrent to intruders who may be trying to break into an embassy or any restricted facility, said Marine Capt. Joseph Kloppel, a spokesman for the Joint Non-Lethal Weapons Directorate, in Quantico, Va. "The whole purpose of a system like this is to see what the person's intentions are.

"It gives the commander on the ground options other than tear gas and more of a flexible response," he said.

The Mobility Denial System consists of three parts, explained Bill Mallow, one of the inventors of MDS at the Southwest Institute, in San Antonio, Texas. One component is a liquid polymer emulsion, the other component is a polymeric powder that produces a slurry, which then is pumped into a nozzle where it meets a stream of water.

"When it hits the water it turns into a viscous, elastic, sticky, slimy, slippery gel," he said. "The resulting gel is 95 percent water, and the other 5 percent is a polymer pretty much used in soft contact lenses and baby diapers as an absorbent."

The gel remains slippery for many hours. "When it dries, it can be swept away or be reactivated with water," Mallow said. The anti-traction substance is effective at surface temperatures ranging from 32 to 125 degrees Fahrenheit and lasts for six to 12 hours.

The substance sticks to grass, asphalt, concrete, wood, metal, walls and most other surfaces, Mallow said. "On walls, it prevents people from bringing ladders. ... The ladder will slip and the person will fall."

The gel also can be sprayed on people, in which case, "it would make them extremely miserable and distract them from any intentions they had," Mallow said. "It makes door knobs and windows totally inaccessible."

What makes MDS work is the powder that is mixed with water to create the gel.

Trying to walk on the slurry substance can cause injuries, explained Mallow. "People can't control the way they fall," he said. "The fall can be traumatic." Once the substance comes in contact with water, it reacts instantaneously.

Mallow said that there are serious concerns about the psychological and physical dangers of the Mobility Denial System. "I don't know who is going to account for the broken legs," he said. "Also, [people] will be a slimy mess of worms."

"It is non-lethal, but it can be lethal," he added. When they fall, people can...