Accidental poisoning and chemical burn injury in young children is a worldwide problem. A globally adopted system of labelling hazardous substances is intended to reduce this risk, but the pictograms that are central to this are often misunderstood. We sought to discover children’s interpretation of Globally Harmonised System of Classification and Labelling of Chemicals pictograms, to promote greater awareness and understanding of them, and to inform public health messages and teaching in schools.
An in-person, single-group pretest and post-test intervention study was conducted using an electronic self-completed programme. Children reported perceived meaning of 9 pictograms, which were then explained with examples, before immediate post-test of the pictograms’ intended meaning and multiple choice quiz to reinforce learning. An optional family-based activity was included.
Only 36% understood the sign for ‘toxic’ substances. The ‘corrosive’ pictogram was understood by 53%, but 11% mistook the image to indicate a place or substance for handwashing. The pictogram for ‘gas under pressure’ provoked incorrect responses from 94%. For these three, post-test showed remarkable improvement (87%, 73%, 75%, respectively). There was little understanding of ‘health hazard’, ‘hazardous to the aquatic environment’, ‘harmful irritant’ and ‘oxidising agent’ pictograms. Post-test results remained disappointing.
Alternative means of responding such as sorting true/false statements, or drawing lines to connect correct objects with corresponding pictograms could be considered for younger children. There was a need to show the pictograms in context for better understanding. Despite a dangerous lack of understanding initially, the programme achieved short-term retention of knowledge at post-test. Secondary prevention opportunities should also be explored.