None of the substance was found at the scene of the stabbings in Southport and police said the poison they did discover presented a low risk to the public.
Dr Renu Bindra, senior medical advisor at the UK Health Security Agency, said: “There has been no evidence of ricin poisoning in anyone involved or connected to this incident.”
The charges which have been added do not require a motive to be established.
In order for the incident to be classed as a terrorist incident, motive would need to be established.
The teenager has already been charged with murdering Bebe King, six, Elsie Dot Stancombe, seven, and Alice da Silva Aguiar, nine, at a Taylor Swift-themed dance class.
He is also charged with ten counts of attempted murder and possession of a knife.
A trial is expected to begin in January.
The top stories and transfer rumours from Tuesday's newspapers...DAILY MAIL Real Madrid scouts have checked on Adam Wharton since
Millwall goalkeeper could face further punishment for his horror challenge on Jean-Philippe Mateta. Crystal Palace striker Mateta was taken to hospital after be
Despite being one of the most famous quotes in British politics, former Prime Minister James Callaghan did not actually say “Crisis? What crisis?” when he r
The summit of European leaders in London on Saturday to discuss the war in Ukraine dominates the front pages.The i paper says, external Britain and France have