If you qualify for the hardship provisions specified in 40 CFR 1068.245 , we may approve a period of delayed compliance for up to one model year total (or two model years total for small-volume manufacturers). If you qualify for the hardship provisions specified in 40 CFR 1068.250 for small-volume manufacturers, we may approve a period of delayed compliance for up to two model years total.
40 C.F.R. §1039.635