Passive Ink Staining: The effective answer to the growing problem of ATM explosive attacks

ATMs are a highly attractive target for criminals due to the large volume of cash inside them, easy access and the ubiquity of similar protection measures. For more than 15 years, criminals have used gas or solid explosives to gain access to the cash inside ATMs. What is new, is the rise in the number of explosive attacks, and the speed with which they are spreading.

The scary reality of today, is that the cycle of ATM violence has reached the point at which ATM explosions now seriously jeopardise the safety of the public. 

In response to the growing numbers of the attacks, the level of physical protection has been increased, for example, so-called ‘explosive resistant’ safes. However, using stronger safes simply generates a vicious circle of criminals applying more and more explosives.  This results in an even greater risk to public safety. 

The industry needs a more effective approach to address ATM explosive attacks.

Why ATM explosive attacks become such a dangerous threat? 

When ATMs were first installed back in the 1960s, protection from physical attacks was geared to the only internationally recognised safe standard at that time, UL 291 Level 1. This approved safe design was later copied and offered as the standard ATM safe, resulting in a widespread installed base of UL 291 Level 1 safes globally. 

Safe standards have evolved since then to provide more resistance. Some safe designs are still vulnerable to new criminal methods, such as thermal tools and hammers, crowbars, drills or cutting torches. However, all safes have one thing in common. They are all vulnerable to explosive attacks.

The ATM industry has constantly been searching for solutions to the problem but has had no success.

Some of these solutions included additional physical security features such as stronger shutter mechanisms which were added to the ATM to try and prevent the insertion of explosives. Stronger, heavier safes were also used to protect the cash against an explosive blast, and other measures such as smoke screens and CCTV were deployed. 

However, criminals are persistent and bring more and more explosives, typically doing a ‘double– knock’ attack to ensure they access the cash inside the ATM. This has resulted in increased collateral damage and an even greater risk to human life. 

This highlights just how important it is to addresses the root cause of the escalating problem of ATM explosive attacks and find a route to end this cycle of violence.

Passive and Active: Two types of ink staining systems 

Ink-staining systems are used as a defence against explosive attacks because ink serves as a criminal deterrent by ‘spoiling the prize’. There are two types of ink staining systems:

  1. Active ink staining, also known as IBNS (Intelligent Banknote Neutralisation System): an electronic/ battery powered solution with sensors which trigger the release of ink if the explosion is detected. 
  2. Passive ink staining:  the ink containers instantly rupture with the shock wave of the explosion and immediately release the ink. There are no electronics, batteries or sensors. 

Why is Passive Ink Staining so effective?

Passive ink staining uses game-changing shockwave technology, this is different to all other ink-staining solutions as it does not rely on sensors to detect an explosion and activate the ink.

Some of the benefits of the passive ink staining include:

  • Fast and reliable reaction to an explosion: Passive ink staining is specifically designed to instantaneously rupture on explosive impact and effectively stain the notes inside the cassettes. 
  • No risk of false activations: There is no risk of false activations because there are no sensors and consequently no impact on ATM servicing and replenishment. 
  • Proven to reduce attacks on ATMs: Passive ink staining has been installed in more than 16,000 ATMs in South Africa by major ATM deployers and the number of explosive attacks has reduced dramatically.  
  • High Security: Passive ink staining cannot be disconnected or tampered with as the ink will always be activated on explosive impact.
  • More ink for maximum note coverage: The passive ink staining solution can hold double the volume of ink compared with IBNS systems. This means that the notes are more thoroughly stained in an explosion. It is proven to stain 100% of the notes in the cassette with most of the surface area of each note covered in ink. This solution has been approved by international industry testing authorities. 
  • Peace of mind: Due to passive ink staining only being activated by the shockwave impact of an explosion, it means it is not affected by external influences such as weather or temperature, power shortages or battery life. Its effectiveness is in the simplicity of its passive design.
  • Maximum note capacity:  Unlike other dye-stain solutions, the ink is typically located in the lid of the cassette meaning the note capacity of the cassette is not affected. This results in CIT costs not being affected because the note capacity remains the same, so no increase in cash management costs.
  • Versatile and cost effective: Passive ink staining can be retrofitted into all cassettes and works with all bank note denominations and types, including polymer. It does not have any health and safety concerns and is cost effective and low maintenance.  


ATM deployers once believed they had no other alternative than to take ATMs out of locations where explosive attacks could be a serious risk to human lives.

Passive ink staining tackles the persistent and dangerous threat of explosive attacks, breaking the cycle of ATM violence and most importantly reducing the risk to public safety.

Related articles
TMD Launches Defenses to Protect Cash Inside the ATM and Branch
ATM Marketplace podcast with Claire Shufflebotham: ATM Security Threats
10 reasons why passive ink-staining is the only effective defence
Ⓒ TMD Security, 2024- All Rights Reserved
Request a demo