## Facts

- White Mountain Health Center, Inc., an Arizona nonprofit, sought to open a medical marijuana dispensary in Sun City under the Arizona Medical Marijuana Act (AMMA).
- The AMMA required applicants to obtain local zoning documentation as part of the state dispensary registration process.
- Maricopa County refused to issue the zoning certification, asserting that doing so would facilitate conduct prohibited by the federal Controlled Substances Act (CSA) and could expose county officials to federal criminal liability.
- The County adopted a zoning “Second Text Amendment” that added restrictive conditions affecting where dispensaries could operate.
- The Arizona Attorney General intervened, arguing the AMMA dispensary scheme conflicted with the CSA and was preempted under the Supremacy Clause.
- White Mountain filed suit seeking declaratory and injunctive relief requiring issuance of the zoning documentation and challenging the restrictive zoning amendment.
- The superior court granted partial summary judgment for White Mountain on preemption, ruled officials did not face federal criminal exposure for administering AMMA-related zoning/permitting, and invalidated the Second Text Amendment as applied to dispensaries.
- The County and State appealed; the appellate court consolidated appeals addressing preemption and zoning.

## Issues

1. Whether the CSA preempts the AMMA’s authorization and regulation of medical marijuana dispensaries under conflict-preemption theories (impossibility and obstacle preemption).
2. Whether county officials administering AMMA-required zoning documentation face federal criminal liability under the CSA such that compliance with state law is “impossible.”
3. Whether the AMMA’s dispensary scheme poses an impermissible obstacle to congressional objectives in the CSA.
4. Whether the County’s zoning “Second Text Amendment,” as applied to dispensaries, conflicts with and is invalid under the AMMA’s regulatory framework.

## Decision

- The court affirmed the superior court’s principal rulings for White Mountain.
- The CSA did not preempt the AMMA’s dispensary provisions under either impossibility or obstacle preemption.
- County and state officials could implement AMMA-related zoning and permitting requirements without violating the CSA merely by performing administrative acts required by state law.
- The County’s Second Text Amendment was invalid as applied to medical marijuana dispensaries because it conflicted with the AMMA’s statewide scheme and impeded implementation.

## Legal Principles

- In the absence of express or field preemption, federal law preempts state law only to the extent of an actual conflict.
- Impossibility preemption does not apply where federal law regulates private conduct and state law does not require anyone (including officials) to engage in federally prohibited acts; administering a state licensing/zoning process is not itself a CSA offense.
- Obstacle preemption does not arise solely because a state declines to criminalize certain conduct under state law; federal authorities remain able to enforce federal prohibitions.
- Local zoning measures that effectively prevent or materially thwart implementation of a state-created dispensary licensing and siting framework conflict with state law and may be invalidated as applied.

## Conclusion

The court held that Arizona’s medical marijuana dispensary system can operate alongside the federal CSA because the AMMA does not require violations of federal law or block federal enforcement, and it required Maricopa County to perform AMMA-mandated zoning functions while rejecting county zoning restrictions that conflicted with the state’s dispensary regulatory scheme.


White Mountain Health Ctr., Inc. v. Maricopa Cnty., 241 Ariz. 230, 386 P.3d 416 (Ct. App. 2016)