The Paradise Palms neighborhood in Las Vegas, Nevada sits atop an invisible threat—a plume of tetrachloroethylene (PCE/PERC) contamination that originated from a former dry cleaning business nearly a mile away. This chemical plume, stretching more than a mile long and up to 1,000 feet wide beneath homes and businesses, represents one of Nevada's most significant groundwater contamination cases. Despite being discovered in 2000, remediation efforts were delayed for years by litigation and funding disputes.
Origin and discovery of the contamination
The PCE contamination originated from the Al Phillips the Cleaners business that operated at 3661 South Maryland Parkway in the Maryland Square Shopping Center from 1969 to 2000. Court records documented a major spill of approximately 100 gallons of pure PCE inside the facility in 1982, with some of the chemical going directly down a drain. Evidence suggests multiple smaller releases also occurred through routine operations and machine maintenance.
The contamination remained undetected for 18 years until November 29, 2000, when it was discovered during a routine environmental inspection performed as part of a property transaction when the Clark County School District considered purchasing the property. The Nevada Division of Environmental Protection (NDEP) received an initial environmental report on July 21, 2001.
Subsequent investigations revealed a troubling picture:
- 2002 NDEP determined PCE had migrated off-site
- 2003-04 Monitoring wells confirmed the plume had traveled beneath the Boulevard Mall
- 2005 Testing showed the plume had reached the residential neighborhood
- 2006 Wells installed in Paradise Palms confirmed contamination had reached homes
- 2007 Soil gas testing revealed potential for PCE vapor intrusion into homes
Extent of the groundwater plume
The PCE plume extends in an easterly direction from the original Maryland Square source, flowing beneath Maryland Parkway, under the Boulevard Mall, beneath approximately 200 homes in the Paradise Palms neighborhood, and extending to the Las Vegas National Golf Club. The plume's dimensions are substantial:
Plume Characteristics
- Length: Over one mile long from source to edge
- Width: Ranges from 400 to 1,000 feet
- Depth: Extends up to 70 feet deep in some areas
- Concentration: PCE levels as high as 11,000 parts per billion (ppb) near the source—2,200 times the EPA safe drinking water standard of 5 ppb
The contamination follows natural groundwater flow patterns from west to east through the subsurface. Though the plume doesn't affect Las Vegas's municipal drinking water supply, it creates another hazard—vapor intrusion. PCE can evaporate from groundwater, travel upward through soil, and enter homes through foundation cracks.
Health risks from PCE exposure
PCE is a manufactured chlorinated compound classified by the EPA as "likely to be carcinogenic to humans by all routes of exposure." Health risks associated with exposure include:
Short-term effects:
- Central nervous system impacts: dizziness, headaches, confusion
- Respiratory tract irritation
- At very high concentrations: unconsciousness
Long-term effects:
- Neurological damage: impaired cognitive function, visual perception, attention
- Liver and kidney damage
- Increased cancer risk, particularly for bladder cancer and non-Hodgkin lymphoma
- Potential reproductive and developmental concerns
A human health risk assessment for the Maryland Square site found that without intervention, the greatest carcinogenic risk was estimated at 3 per 100,000 excess cancer cases due to long-term PCE inhalation from indoor air. The non-carcinogenic hazard index was 2.6 times greater than acceptable levels in some areas.
The primary exposure pathway in Paradise Palms is vapor intrusion—PCE evaporating from groundwater, migrating upward through soil, and entering homes. Testing revealed PCE concentrations as high as 170,000 µg/m³ in soil gas on mall property and up to 46,000 µg/m³ in shallow soil gas within the residential neighborhood.
Monitoring well results
The NDEP established a network of monitoring wells throughout the affected area to track contamination. Key findings include:
- Source area: PCE concentrations reaching 11,000 ppb
- Residential area: Parts of the plume under homes had PCE concentrations exceeding 200 times the federal drinking water standard
- Groundwater: Quarterly monitoring reports show contaminant movement and concentration changes
- Indoor air: Testing in 97 homes identified approximately 15 where PCE vapor levels exceeded NDEP's interim-action level of 32 µg/m³
These monitoring results informed both the remediation approach and the installation of home mitigation systems where needed. The NDEP established a remediation standard of 100 µg/L (100 ppb) for groundwater as protective of indoor air, with long-term goals of 9.4 µg/m³ for PCE in indoor air.
Cleanup efforts and timeline
Remediation of the Maryland Square PCE site has progressed through multiple phases:
Source Area Soil Remediation (2011):
- August-September 2011: Excavation of contaminated soil at former dry cleaner site
- Additional excavation on northern side based on confirmation sample results
- Treatment of excavation floor with potassium permanganate to degrade residual PCE
- October 2011: Backfilling with clean soil completed
Vapor Intrusion Mitigation:
- Installation of sub-slab depressurization systems in approximately 15 affected homes
- Systems seal home foundations and depressurize the soil to prevent vapor seepage
- Cost estimated at $2,000-$20,000 per home
Groundwater Plume Remediation (Planned 2017):
- Eastern component: Groundwater extraction and above-ground treatment ("pump and treat") system in Boulevard Mall parking lot to prevent further migration into residential area
- Western component: Air sparging with vapor extraction and chemical oxidation near former dry cleaner to reduce PCE mass
- Estimated cost: $5.7-7.9 million
- Estimated cleanup timeframe: 3-10 years from implementation
The cleanup effort was significantly delayed by years of litigation to determine financial responsibility. When remediation began in 2017, NDEP hoped it would be completed on the shorter end of the 3-10 year timeframe.
Legal proceedings
Several significant legal actions shaped the response to this contamination:
Homeowner Lawsuit (2008):
- Case: Voggenthaler v. Maryland Square LLC
- Filed under Resource Conservation and Recovery Act (RCRA) seeking injunctive relief
- July 2010: Federal district court granted summary judgment for homeowners, ordering cleanup
NDEP Lawsuit (2009):
- Nevada Division of Environmental Protection v. Maryland Square Shopping Center LLC, et al.
- Filed under CERCLA (Superfund) and state law seeking cost recovery and injunctive relief
- Court granted summary judgment in favor of NDEP for past response costs
Ninth Circuit Appeal (2013):
- Affirmed summary judgment for homeowner plaintiffs
- Affirmed summary judgment for NDEP for past response costs
- Rejected claims that CERCLA application violated the Commerce Clause
- Clarified Maryland Square failed to establish the bona fide prospective purchaser defense
The courts identified several responsible parties, including the Shapiro Bros. Investment Company (operated dry cleaner 1969-1984), Johnson Group/DCI USA (operated dry cleaner 1984-2000), Herman Kishner Trust (property owner during spills), and subsequent property owners. The Herman Kishner Trust, which owned the shopping center when the spill occurred, controlled the cleanup funds.
Government agencies involved
Multiple government agencies have played roles in addressing this contamination:
- Nevada Division of Environmental Protection (NDEP): Lead agency responsible for site investigation, oversight of remediation, enforcement actions, and public notification and testing coordination
- U.S. Environmental Protection Agency (EPA): Provides regulatory framework through CERCLA and RCRA and establishes health standards for PCE exposure
- Federal Courts: U.S. District Court for the District of Nevada and U.S. Court of Appeals for the Ninth Circuit
- Clark County: Local government coordination and Commissioner's office for district including Paradise Palms
Current status
As of 2017, the remediation plan was being finalized with responsible parties, with groundwater extraction scheduled to begin that spring. The cleanup was estimated to take between 3-10 years from implementation, potentially placing completion between 2020-2027 if the plan proceeded as scheduled.
The Nevada Environmental Activities (NEA) database maintained by NDEP contains the most current information about site status, though accessing detailed reports requires creating a user account. Despite the contamination issues, Paradise Palms has remained a desirable neighborhood due to its historic mid-century modern architecture, with approximately 40 residential sales occurring in the affected area during a two-year period preceding 2016.
This case highlights the lasting environmental impacts of industrial practices and the challenges of addressing legacy contamination in urban areas. The cleanup effort, though delayed by litigation and funding issues, demonstrates a comprehensive approach to remediation involving source area treatment, hydraulic containment, and vapor intrusion mitigation to protect public health.