HELLEBORE	HEMLOCK, WATER	HYDROCARBONS (external exposure)
HELLEBORE, COMMON WHITE	HENBANE	HYDROCARBONS (ingestion)
HEMLOCK WATER DROPWORT	HEPTENOPHOS	HYDROGEN SULPHIDE (H2S)
HEMLOCK, GIANT	HOLLY	HYPERICUM
HEMLOCK, LESSER	HORSETAIL