Researchers warned about the risks of giant hogweed after it was recently spotted in Virginia for the first time.
Warnings have been issued in previous years after discoveries in Michigan, New York and elsewhere in the Northeast, Midwest and Pacific Northwest.
Sap on the plant's leaves, roots, flower heads, seeds and stem hairs can cause permanent blindness if it gets in a person's eyes.
The sap can also cause blistering and scarring if it gets on bare skin.
Health officials say to wash skin if it comes in contact with the plant, immediately flush eyes with water, and promptly seek medical attention.
The plant can grow up to 18 feet tall, has a green stem with bristles and dark red or purple spots, and has a white flower.
It is most commonly found in New England, the Mid-Atlantic region and the Northwest, often growing along streams and rivers and in fields, forests, yards and roadsides, experts say.