(a) In General.—The United States may obtain in a civil action an injunction against—

(1) the conduct prohibited under section 175 of this title;

(2) the preparation, solicitation, attempt, threat, or conspiracy to engage in conduct prohibited under section 175 of this title; or

(3) the development, production, stockpiling, transferring, acquisition, retention, or possession, or the attempted development, production, stockpiling, transferring, acquisition, retention, or possession of any biological agent, toxin, or delivery system of a type or in a quantity that under the circumstances has no apparent justification for prophylactic, protective, or other peaceful purposes.

(b) Affirmative Defense.—It is an affirmative defense against an injunction under subsection (a)(3) of this section that—

(1) the conduct sought to be enjoined is for a prophylactic, protective, or other peaceful purpose; and

(2) such biological agent, toxin, or delivery system is of a type and quantity reasonable for that purpose.