The Waiver of Informed Consent may apply in circumstances where research poses no incremental risk to a subject. The regulations for this Waiver are in the CFR Section 46.116 - subpart D:
CFR §46.116 General requirements for informed consent.
(d) An IRB may approve a consent procedure which does not include, or which alters, some or all of the elements of informed consent set forth in this section, or waive the requirements to obtain informed consent provided the IRB finds and documents that:
(1) The research involves no more than minimal risk to the subjects;
(2) The waiver or alteration will not adversely affect the rights and welfare of the subjects;
(3) The research could not practicably be carried out without the waiver or alteration; and
(4) Whenever appropriate, the subjects will be provided with additional pertinent information after participation.