Environmental Consulting


Leighton has supported development plans for more than 2,000 sites throughout California, determining viability through a range of specialized environmental engineering and consulting services.

These services include:

  • Caltrans Initial Site Assessment (ISA)
  • Phase I Environmental Site Assessments (ESAs)
  • Phase II ESAs, including carefully planned and executed subsurface investigations
  • Performance-based remediation design, implementation and management
  • Litigation Support
  • Remedial Excavation
  • Soil Vapor/dual phase extraction
  • In-Situ chemical oxidation/reduction
  • Preparation and management of environmental compliance plans
  • CUPA Hazardous Material Management Plan (HMMP)
  • Hazardous Material Inventory Statements (HMIS)
  • Underground Storage Tank Program audits

Due Diligence.

During site due diligence, Leighton makes careful consideration of:

Site Conditions


Type and Extent
of Contaminants

Time Frame Available to Conduct a Remediation Program

Site Remediation.

Our team then immerses ourselves in the data and goals, weighing the options to identify remediation solutions that are best suited to your project’s budget and schedule.

Site remediation services include:

  • Oversight of contaminated site assessments and cleanups
  • Groundwater assessment and remediation
  • Human health risk assessments
  • Remediation system operations and maintenance
  • Vapor intrusion assessment and remediation
  • Regulatory compliance and permitting
  • Coordination of proper handling, storage and removal of contaminants
  • Manifest documentation and reporting based on the Site Safety Plan and Environmental Compliance Plan



Leighton’s specialized knowledge of environmental regulations helps clients effectively navigate various agencies, specialized trainings, and required documentation.

Our team has a robust understanding of:

  • Title 40 Code of Federal Regulations
  • California Health & Safety Code
  • California Code of Regulations
  • Various local municipal codes

Leighton’s regulatory compliance services include:

  • Distinguishing the applicable regulatory body
  • Providing inspections, audits, or training to meet Certified Unified Program Agency (CUPA) standards

Read More about our expertise.

I-215 Placentia Avenue Interchange

SR-55 Widening

Perris Valley Line

California High School Stadium