Giant Hogweed damage - just touching it will cause horrendously large and painful blisters and severe rashes, which are hard to heal, it can cause blindness, severe sun sensitivity. Looks like Queen Anne's Lace but it grows to 15-20 feet with the flower clusters 2.5-3' wide and huge leaves.
News - Plant that can cause third-degree burns popping up in Canada - The Weather Network Giant Hogweed.
Giant Hogweed Identification
Giant hogweed is an invasive, tall, robust, herbaceous biennial. It can grow up to 20 feet tall with large hollow stems. The sap of a mature giant hogweed causes phytophotodermatitis. Sap contacting with skin in the presence of sunlight will causes severe rashes, blisters, and skin discoloration. Eradication is a must.