Pine processionary development, pine processionary caterpillars are highly irritating to the skin. Contact with the hairs of the caterpillar can cause severe rashes (urticaria) and eye irritation. Some individuals may have an allergic reaction to the caterpillar's hairs. 5th stage larvae can eject hairs when threatened or stressed; the hairs, which have the form of harpoons, then penetrate and irritate all areas of exposed skin nearby with an urticating protein. Allergic reactions may follow in susceptible individuals on subsequent exposure to the hairs. The pine processionary is an economic pest in coniferous forests in southern Europe. It is controlled to some extent
Hazard substitution data, making alternatives assessments difficult. Another type of regrettable substitution involves shifting the burden of a hazard to another party. One example is that the potent neurotoxin acrylamide can be replaced with the safer "N"-vinyl formamide, but the synthesis of the latter requires use of the highly toxic hydrogen cyanide, increasing the hazards to workers in the manufacturing firm. In performing an alternatives assessment, including the effects over the entire product lifecycle as part of a life-cycle assessment can mitigate this. Hazard substitution Hazard substitution is a hazard control strategy in which a material or process is replaced with another