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Pacific Southwest, Region 9

Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations

Federal Rule Requirements for the Agricultural Sector in Maricopa County

NOTE: This content is no longer being updated. The most up to date information can be found in Federal Register Notices and Approved Air Quality Implementation Plans in Region 9.


The Arizona Department of Environmental Quality (ADEQ) Plan for Attainment of the 24-hour PM-10 Standard, Maricopa County PM-10 Nonattainment Area (the "Microscale Plan") demonstrated that agricultural fields and aprons contributed to exceedances of the 24-hour standard at monitoring sites in the nonattainment area. These exceedances were caused by wind-blown particulates. The monitoring sites were typical of the numerous agricultural-urban interface areas in the nonattainment area.

Since the Microscale Plan did not address specific remedies for particulate control, also known as Reasonably Available Control Measures (RACM), from agricultural sources, it was necessary that a Federal Implementation Plan (FIP) address agricultural sources.

Stakeholder Discussions

In early 1997, ADEQ, the U.S. Department of Agriculture Natural Resources Conservation Service, and the Maricopa County Environmental Services Department began cooperative, stakeholder-based meetings to address agriculture's contribution to the PM-10 exceedances.

In mid-1997, the Maricopa County Association of Governments began to work with the Maricopa County Farm Bureau on possible strategies to reduce PM-10. Also, at this time, EPA began to meet with the key stakeholders to inform them of the EPA's pending FIP responsibility. In November 1997, EPA staff toured agricultural sites in and around the nonattainment area and met with numerous growers. Between November and March, EPA met on many occasions with the state and local Farm Bureau and other key stakeholders to discuss potential collaborative strategies for the FIP.

Based on these meetings and discussions, there was a general agreement to use a Best Management Practices (BMP) approach for the FIP. It was recommended that the BMP approach be modeled after a similar process used in Arizona to protect groundwater from nitrogen sources.

Final FIP

EPA has finalized an enforceable commitment to adopt and implement RACM for agricultural sources. No control measures are being finalized at this time; rather, EPA will enter into a multi-year process to work with agricultural experts to develop appropriate BMPs to meet the RACM requirement. The final commitment includes a series of enforceable milestones and dates for proposing, finalizing, and implementing the BMPs. EPA is actively involved in stakeholder-based processes to begin formal development of the BMPs. Participants include a variety of stakeholders who represent agriculture, higher education and regulatory agencies.

Proposed FIP rulemaking for RACM: September 1999
Final FIP rulemaking for RACM: April 2000
RACM implementation: June 2000.

FIP Replacement

Parallel with the FIP efforts, EPA has been working closely with the Farm Bureau and ADEQ to develop BMPs through a state-led process intended to replace EPA's FIP measure. The state's Agricultural BMP Committee held its initial meeting in September 1998 and will continue to meet into the foreseeable future until the BMPs are developed. ADEQ recently submitted legislation to EPA authorizing the state-led BMP process. If approved by EPA, the state-led process would replace the BMP strategies in the final FIP.

For more information:

Please contact colleen McKaughan, Associate Director, air Division, U.S. EPA Region 9 at (520) 498-0118. Send questions and comments to r9.phoenixdust@epa.gov.

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