(a) Any person, including any supplier, importer or manufacturer, who sells any toxic substance within the State of Illinois must provide the buyer, within 30 days of the date of receipt, with a material safety data sheet for the toxic substance and must label the container with the chemical name and appropriate hazard warning. The person selling the toxic substance need not provide more than one material safety data sheet for a single toxic substance to a single buyer, unless such buyer requests a second or subsequent material safety data sheet for the toxic substance, in which case the seller shall provide a copy of the material safety data sheet to the buyer within 30 days of receipt of such request.(b) This Section shall become effective with respect to any toxic substance upon filing, unless a later effective date is specified in the rule, pursuant to Section 4(e). P.A. 91-357, eff. 7/29/1999.