20Public health incidents
(1)A public health incident exists if—
(a)a circumstance mentioned in subsection (2), (3), (4), (5) or (6) occurs; and
(b)there are reasonable grounds to suspect that the circumstance is likely to give rise to a significant risk to public health.
(2)The first circumstance is that—
(a)a person has an infectious disease; or
(b)there are reasonable grounds to suspect that a person has such a disease.
(3)The second circumstance is that—
(a)a person has been exposed to an organism which causes infectious disease; or
(b)there are reasonable grounds to suspect that a person has been so exposed.
(4)The third circumstance is that—
(a)a person is contaminated; or
(b)there are reasonable grounds to suspect that a person is contaminated.
(5)The fourth circumstance is that—
(a)a person has been exposed to a contaminant; or
(b)there are reasonable grounds to suspect that a person has been so exposed.
(6)The fifth circumstance is that—
(a)any premises are or any thing in or on premises is infected, infested or contaminated; or
(b)there are reasonable grounds to suspect that any premises are or thing is so infected, infested or contaminated.
(7)In subsection (6), “infected”, “infested” and “contaminated” have the meanings given by section 72(5).