Local emergency services participated in a Major Emergency Exercise earlier today.
The training took place at locations in Louth and Monaghan.
The planned multi-agency training scenario began when two Louth County Council employees discovered tankers dumping a substance into a river near Knockbridge.
Gardai were alerted but the local authority employees were taken hostage by armed men.
This launched the armed support unit who controlled the scene while waiting on trained negotiators who then took over the operation.
At the same time, one of the tankers left for the border but was involved in a road traffic collision near Toome GAA pitch with a bus, which resulted in multiple fatalities.
This was attended by ambulance, Garda and local fire service who decontaminated the scene and helped the injured people off the bus.
The operation was undertaken to help services learn how to deal with possible major emergencies in a correct and safe manner.
Tom Horwell, assistant chief ambulance officer for the North East region explained more about what his staff gained from the day.
A Garda Spokesperson confirmed the operation was a success across the board and the negotiation team, along with the Armed Response Unit were able to diffuse the hostage situation without fatality..