The state of Nebraska committed to conform to the PM10 regulations as set forth in 40 CFR part 51 . In a letter to Morris Kay, EPA, dated February 5, 1988, Mr. Dennis Grams, Director, Nebraska Department of Environmental Control, stated:
An emission inventory will be compiled for the identified Group II areas. If either area is found to be violating the PM10 standards, the inventory will be completed as part of the PM10 SIP for that area on a schedule consistent with that outlined in paragraphs 3, 4, and 5. If the PM10 standards are not violated, the inventory will be completed not later than July 1, 1989, and submitted to EPA not later than August 31, 1990, as part of the determination of adequacy of the current SIP to attain and maintain the PM10 air quality standards.
40 C.F.R. §52.1423