; and (iii) for a portable generator powered by a Class II spark-ignition engine with two cylinders, a rate of 300 grams per hour. (F) A requirement relating to the shutoff capability of a portable generator in an elevated carbon monoxide environment. (G) Other shutoff requirements and test specifications the Commission determines necessary to protect consumers from the risk of injury relating to the use of portable generators. (3) Compliance dates (A) In general Except as provided in subparagraph (B), the Commission shall include in the final standard promulgated under paragraph (1) a compliance date that is not later than 1 year after the date of such promulgation, by which portable generators shall comply with the final standard. (B) Handheld and Class I engines With respect to portable generators powered by handheld or Class I spark-ignition engines, the Commission may include a separate compliance date that is not later than 18 months after the date of the promulgation of the final standard. (4) Review and revision of standard Beginning 1 year after the date of the promulgation of the final standard under paragraph (1) and not less frequently than every 5 years thereafter, the Commission shall review and revise such standard to ensure the highest level of safety feasible with respect to portable generators. (5) Treatment of standard The final standard promulgated under paragraph (1), including any revision of such standard made pursuant to paragraph (4), shall be treated as a consumer product safety rule promulgated under section 9 of the Consumer Product Safety Act ( 15 U.S.C. 2058 ). (b) Interim standard for portable generators (1) Interim standard Beginning on the date that is 6 months after the date of the enactment of this Act and ending on the date that the final standard promulgated under subsection (a)(1) goes into effect, it shall be unlawful for a person to import into or distribute in commerce in the United States a portable generator, unless— (A) the portable generator complies with the