Definition
The domino effect is the possibility that, because establishments are close together and hold dangerous substances, a major accident at one triggers or aggravates a major accident at another. The effect need not be one-way; two establishments can feed each other.
What it requires
- Exchange of information among the group: which substances, what quantities, which scenarios, what effect distances.
- Reflecting that information in each establishment's own policy, management system and safety report.
- Aligning the emergency plans: who informs whom and how, how a joint evacuation would run.
- Cooperating in informing the public and neighbouring establishments.
Why it is neglected
The domino question sits outside every establishment's own fence, and therefore at the edge of everyone's attention. The information exchange is usually done once and never refreshed — yet when the neighbour's stock or process changes, you are the one affected.
What to do in practice
The most robust approach is to turn the exchange into a record: date, information shared, information received, shared assumptions, and the date of the next refresh. That both evidences the duty and makes changes next door traceable.
Joint drills
Whether the alignment actually works shows only in a joint drill: do the radio channels match, can the alarms be told apart, which route is used when the road is blocked. These emerge on the ground, not around a table.