The use of toxic gases is regulated by Royal Decree no. 147 of 9 January 1927, which, in Table 2 of the decree itself, features the list of gases recognised as toxic, for which some limitations and specific conditions are established. Royal Decree no. 147 of 9 January 1927, which has kept its importance intact in the current national regulations, has been a source of inspiration for all subsequent sector regulations.
It sets out the rules for all phases of use of toxic gases (use, custody and storage and transport).