(a) Importations of plants, plant products, plant pests, biological control organisms, noxious weeds, soil, and other products and articles that may be infested or infected by or contain plant pests, biological control organisms, or noxious weeds are exempt from the prohibitions or restrictions contained in parts 319, 330, and 360 of this chapter if they meet one of the conditions in paragraphs (a)(1) through (a)(4) of this section and are moved into the United States and handled in compliance with this part. Provided: That these exemptions do not apply to cotton and covers imported into the United States from any country for exportation or transshipment and exportation or transportation and exportation as provided in §§ 319.8 through 319.8-26 of this chapter. Moreover, the applicable provisions of §§ 330.100 through 330.109 and 330.400 of this chapter also apply to products and articles subject to this part.

(1) They are brought in temporarily where loading and landing is not intended;

(2) They are unloaded or landed for transshipment and exportation;

(3) They are unloaded or landed for transportation and exportation; or

(4) They are intended for unloading and entry at a port other than the port of arrival.

(b) Prohibited or restricted products and articles offered for and refused entry into the United States under parts 319, 330, or 360 of this chapter are subject to the applicable provisions in this part regarding their subsequent handling in this country.

(c)(1) The provisions in this part apply whether the controls over arrival, temporary stay, unloading, landing, transshipment and exportation, or transportation and exportation, or other movement or possession in the United States and Guam are maintained by entry or other procedures of the U.S. Customs Service, Department of the Treasury, or the Customs Office of the Government of Guam, respectively. Such provisions will apply to arrivals in the United States, including arrivals in a foreign trade zone in the United States to which admission is sought in accordance with the Customs regulations in 19 CFR chapter I. Prohibited or restricted products and articles that have entered the United States, been exported pursuant to this part, and returned to the United States are subject to the applicable requirements of this part upon reentry.

(2) Any restrictions and requirements under this part with respect to the arrival, temporary stay, unloading, landing, transshipment, exportation, transportation and exportation, or other movement or possession in the United States of any product or article shall apply to any person who, respectively, brings into, maintains, unloads, lands, transships, exports, transports and exports, or otherwise moves or possesses in the United States such product or article, whether he is the person who was required to have a permit for the product or article or a subsequent custodian of such product or article, and failure to comply with all applicable restrictions and requirements under this part by any such person shall be deemed to be a violation of this part.

(d) Under section 436 of the Plant Protection Act (7 U.S.C. 7756), a State or political subdivision of a State may not regulate in foreign commerce any article, means of conveyance, plant, biological control organism, plant pest, noxious weed, or plant product in order to control a plant pest or noxious weed, to eradicate a plant pest or noxious weed, or to prevent the introduction or dissemination of a biological control organism, plant pest, or noxious weed.