Terrorism: CGL terrorism exclusions and coverage are commonly written around the federal Terrorism Risk Insurance Act definition of a certified act. Under 31 CFR §50.4(b), an act of terrorism is one certified by the Secretary of the Treasury, in consultation with the Attorney General and the Secretary of Homeland Security. An act cannot be certified if aggregate property and casualty losses do not exceed $5,000,000, or if it is part of a war declared by Congress (except for workers' compensation). The certification decision is not subject to judicial review.

The make-available rule: under 31 CFR §50.20, an insurer must make coverage for insured terrorism losses available on terms that do not differ materially from those for other events, and §50.21 applies this at the initial offer and at the initial offer of renewal. If the insured rejects that offer, §50.23 lets the insurer offer different terms or coverage with an exclusion, as long as state law is not violated.

Microbial matter (fungi or bacteria): the ISO Fungi or Bacteria Exclusion (CG 21 67) removes injury or damage that would not have occurred but for fungi or bacteria on or within a building or structure, plus the cost of testing for and cleaning them up. It does not apply to fungi or bacteria in a good or product intended for bodily consumption.

So with this exclusion attached, a claim that indoor mold made tenants sick is excluded, but a diner sickened by bacteria in a meal the insured cooked and sold stays within the CGL.