Israeli defence forces to use sponge bombs to block Hamas tunnels

Israeli military will need to engage in close combat in the tunnel network under Gaza but the rapidly hardening foam will seal off smaller entrances, preventing ambushes.

Israeli soldiers have a special Tunnel Unit team to investigate and dismantle Hamas tunnels like the one above. Picture: Getty Images

The Israeli military has devised a way to block some of Hamas’s networks of tunnels under Gaza by firing sponge bombs, consisting of a chemical compound which forms a rapidly hardening foam.

While the Israeli defence forces will need to engage in close combat in the tunnel network, the foam will seal off the smaller entrances along the way, preventing ambushes. Sponge bombs were not designed to destroy tunnels but to reduce the odds for the Israeli soldiers by filling up at least some of them with the hardened foam to ease their path down the so-called Gaza Metro.

“The threat of Hamas tunnels will be one of the most significant challenges to contend with,” said John Spencer of the Modern War Institute at the US West Point Military Academy, during a discussion on the issue this month.

“Many miles of these tunnels crisscross below the surface of Gaza, some as deep as 230ft (70m) underground, and collectively offer Hamas fighters the means to protect themselves against the Israeli offensive, manoeuvre undetected below the surface and launch attacks before returning to the security of the tunnels,” he added.

“Is it feasible to seal them? Can they be destroyed with bunker-buster munitions or other explosives? Are there other ways to render them unusable?”

The sponge bomb concept is one of the devices expected to be used to seal the gaps where Hamas terrorists might be hiding and to help flush them out while attempting to rescue the 200 or so hostages that are still being held in the tunnel complex that stretches for hundreds of miles.

The innovative form of defensive warfare will only play a small part in meeting the threats posed by the layers of tunnels. But IDF soldiers have tried out the sponge bomb technique at the Tze’Elim army base near the border with Gaza where there is a mock tunnel system for training exercises.

The use of sponge bombs is not without risk. The chemical-based foam can be hazardous to work with, and some Israeli soldiers have lost their sight through mishandling during training, The Telegraph reported.

The IDF said this month it had been targeting parts of the tunnel network. Assessing the size of the network is difficult, but Hamas has previously claimed it stretched to 500km – about 100km longer than the London Underground network, most of which lies above ground.

The Times