22 U.S. Code § 4343 - Regulations
The Secretary of State may issue regulations to carry out the purposes of this chapter. The primary purpose of such regulations and related policies, rules, and procedures shall be to assure that employees and members of their families do not profit personally from sales or other transactions with persons who are not themselves entitled to exemption from import restrictions, duties, or taxes.
Such regulations shall require that, to the extent contractors enjoy importation or tax privileges in a foreign country because of their contractual relationship to the United States Government, after the effective date of this chapter contracting agencies shall include provisions in their contracts to carry out the purpose of this chapter.
In order to ensure that due account is taken of local conditions, including applicable laws, markets, exchange rate factors, and accommodation exchange facilities, such regulations may authorize the chief of mission to each foreign country to establish more detailed policies, rules, or procedures for the application of this chapter within that country to employees under the chief of mission’s jurisdiction.