Ill. Admin. Code tit. 35, § 223.250 – Product Dating

a) Each manufacturer of a consumer product subject to Section 223.205(a) shall clearly display on each consumer product container or package the day, month, and year on which the product was manufactured, or a code indicating such date.
b) A manufacturer who uses the following code to indicate the date of manufacture shall not be subject to the requirements of Section 223.255(a), if the code is represented separately from other codes on the product container so that it is easily recognizable:
YY DDD = year year day day day
Where:
YY = Two digits representing the year in which the product was manufactured
DDD = Three digits representing the day of the year on which the product was manufactured, with "001" representing the first day of the year, "002" representing the second day of the year, and so forth (i.e., the "Julian date")
c) This date or code shall be displayed on each consumer product container or package no later than the effective date of the applicable standard specified in Section 223.205(a).
d) The date or date-code information shall be located on the container or inside the cover/cap so that it is readily observable or obtainable by simply removing the cap/cover without irreversibly disassembling any part of the container or packaging. For the purposes of this subsection, information may be displayed on the bottom of a container as long as it is clearly legible without removing any product packaging.
e) The requirements of this Section shall not apply to products containing no VOMs (as defined in Section 223.203), or containing VOMs at 0.10% by weight or less.