Blue is for health, the red is for flammability, and yellow is for chemical reactivity.
蓝色代表健康， 红色代表易燃性， 黄色代表化学反应性。
英语百科
Reactivity (chemistry)
（重定向自Chemical reactivity）
Reactivity in chemistry refers to
The chemical reactivity of a single substance (reactant) covers its behaviour in which it:
The chemical reactivity of a substance can refer to the variety of circumstances (conditions that include temperature, pressure, presence of catalysts) in which it reacts, in combination with the: