What CSC does

Clark Seif Clark, Inc. (CSC) is a US-based environmental consulting firm founded in 1996 in Chatsworth, California. The company provides industrial hygiene, environmental engineering, health and safety, and regulatory compliance services, including hazardous building material surveys (asbestos, lead-based paint, PCBs), biohazard and Legionella assessments, indoor air quality testing, OSHA compliance consulting, site assessments, and litigation support with expert witness testimony. CSC serves four primary customer segments: insurance companies and law firms requiring expert testimony on environmental contamination and exposure cases; federal, state, and local government agencies (including EPA, DOE, US Air Force, US Navy, Army COE, US Forest Service, and BLM); corporations and employers needing OSHA and industrial hygiene compliance; and property owners/real estate professionals requiring pre-transaction assessments and post-disaster (e.g., wildfire) evaluations.

The firm's revenue model is professional services on a project-based, quote-driven basis. Pricing is not publicly disclosed; current promotions include a 30th Anniversary new-client discount of 10% off labor costs (capped at $500 per project, April 2026). Distribution is direct: clients engage CSC by phone (800-807-1118) and email, with a client login portal for ongoing work. GTM is sales-led and relationship-driven, supported by content marketing (blog, case studies, videos, press releases, Constant Contact newsletter), client testimonials, and thought leadership. Operations run from three offices (Chatsworth HQ, Lakewood CA, Phoenix/Chandler AZ), with service delivery nationwide and particular depth in California and Arizona regulatory environments. CSC also holds two registered inventions (a Disposable Fit Test Hood for N95 respirators and Sewer Gas Solutions) and was acquired by global consulting firm J.S. Held on May 12, 2026, to expand West Coast industrial hygiene and catastrophe-response capabilities.

Name

CSC

Legal name

Clark Seif Clark, Inc.

Website

https://csceng.com

Company type

Private

Founded year

1996

Operating status

Acquired

Headcount range

11–50 employees

Short description

CSC provides environmental compliance, industrial hygiene, and engineering consulting services, including hazardous materials surveys, indoor air quality testing, and expert witness support, to insurance companies, law firms, government agencies, and corporations nationwide from offices in California and Arizona.

Ownership category

akta.pro rank

Product category

Environmental Consulting Services

NAICS

Environmental Consulting Services (541620), Testing Laboratories and Services (54138), Other Scientific and Technical Consulting Services (54169)

SIC

Services-Testing Laboratories (8734), Services-Management Services (8741)

akta.pro primary industry

Environmental Compliance & Permitting (BPAHAJAA)

akta.pro secondary industry

Environmental Enforcement Defense & Consent Order/Settlement Support (NOV Responses, Corrective Action Plans) (EUAHABAI)

Keywords

• Environmental consulting services
• Industrial hygiene services
• Hazardous materials testing
• Indoor air quality assessments
• OSHA compliance consulting

Headquarters

HQ city

Chatsworth

HQ country

United States

HQ region

North America

Offices3 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Marketing or Sales, Technology or R&D, Others

Revenue model

1. Environmental Consulting Services: Professional consulting services including industrial hygiene assessments, health and safety program development, OSHA compliance consulting, and environmental engineering. Revenue is generated through project-based engagements with clients including insurance companies, legal counsel, government agencies, and corporations.

Pricing tiers

Go-to-market motion1 record

Distribution channels1 record

Marketing channels6 records

Core offering

CSC provides professional environmental consulting, industrial hygiene, and building science services to identify, assess, and mitigate exposure to chemical, biological, physical, and ergonomic hazards. Core service lines include Health & Safety (hazardous materials surveys, biohazard assessments, indoor air quality, OSHA compliance), Engineering, Environmental Consulting (site assessments and remediation strategies), and Litigation Support (expert witness testimony and forensic analysis). Services are sold on a project-based, quote-driven basis to insurance companies, law firms, government agencies, corporations, property owners, and healthcare facilities across the United States.

Product overview

Clark Seif Clark, Inc. (CSC) is an environmental consulting firm offering a unified suite of professional services centered on industrial hygiene, environmental engineering, health and safety, and regulatory compliance. The portfolio includes core service lines for Health & Safety Services (covering hazardous materials surveys, biohazard assessments, indoor air quality, industrial hygiene, and OSHA compliance), Engineering Services, Environmental Consulting (site assessments), and Litigation Support (expert witness and forensic analysis). Supporting these core offerings are specialized service modules such as Lead Paint Services, Wildfire Response Services, Microbial Contaminant Testing, and Safety Training & Education Programs. CSC also provides informational educational videos on environmental health topics. The company serves insurance companies, legal counsel, corporations, and government agencies nationwide from offices in California and Arizona.

Differentiator

Problem solved

Functional benefit

Products and services

• Health & Safety Services Comprehensive occupational health and safety consulting including hazardous building material surveys (asbestos, lead-based paint, PCBs, universal wastes), biohazard assessments, indoor air quality assessments, industrial hygiene services, and OSHA-compliance consulting. Designed for corporations, government agencies, healthcare facilities, and property owners needing regulatory compliance and worker/occupant safety assurance.
• Engineering Services Environmental engineering consulting services for projects requiring specialized technical expertise in assessing and addressing environmental hazards. Supports site characterization, remediation design, and engineering evaluation for clients across commercial, industrial, and government sectors.
• Environmental Consulting Environmental site assessments and consulting services to identify contamination, evaluate risks, and develop remediation strategies for soil, groundwater, and other environmental media. Used by property owners, government agencies, and legal counsel for due diligence, regulatory compliance, and transaction-related environmental reviews.
• Litigation Support Services Expert witness testimony and consulting for environmental cases, including environmental sampling, testing, forensic analysis, independent laboratory testing, regulatory research, and strategic support throughout discovery, deposition, and trial. Used by law firms and insurance companies handling environmental contamination, exposure, or regulatory compliance disputes. CSC has supported over 100 cases in state and federal matters.
• Lead Paint Services Expert lead paint inspection, risk assessment, abatement project monitoring, and compliance services including lead-based paint inspection, lead hazard screens, blood lead investigations, and awareness training. Serves property owners, schools, government agencies, and contractors needing federal/state lead-based paint regulatory compliance (EPA, CDPH).
• Indoor Air Quality Assessments Assessment, testing, and consulting services to identify and mitigate indoor air quality risks including mold, fungi, volatile organic compounds (VOCs), microbial contaminants (e.g., Cladosporium), and ventilation-related issues. Used by property owners, healthcare facilities, schools, and legal counsel to ensure healthy indoor environments and support indoor air quality-related claims.
• Wildfire Response Services Post-wildfire environmental services including soil assessment, ash sampling, smoke damage inspections, source evaluations, and hazardous materials assessment for properties impacted by wildfires. Supports insurance claims professionals, property owners, and legal counsel following Wildland-Urban Interface (WUI) fire events.
• Safety Training & Education Programs Custom safety training programs including OSHA-required training, site-specific safety training, and interactive multi-media learning formats for workforce empowerment. Includes respirator fit testing and training (annual OSHA requirement) for healthcare professionals and other workers. Targets corporate safety directors, EHS managers, and facility managers.

Quantifiable outcome

• Over 100 cases supported as expert witness in state and federal matters
• +1 more outcomes

Named customers4 records

Segments4 records

Ideal customer profiles5 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature2 records

Partnerships

One partnership is on record.

• J.S. HeldflagshipStrategic or Co-development Partner · 12 May 2026J.S. Held, a global consulting firm combining technical, scientific, financial, and strategic expertise, acquired Clark Seif Clark (CSC) to expand its West Coast industrial hygiene capabilities. The acquisition enhances J.S. Held's ability to serve insurance companies, legal counsel, corporations, and government agencies while strengthening rapid response to environmental crises and catastrophes in the region. CSC joins as part of J.S. Held's environmental, health, and safety practice area.

Scale indicators3 records

Recent moves7 records

Expansion highlights6 records

Broad incumbents

• GHD: Global professional services network with significant environmental, water, and building sciences practices, providing EHS consulting and site assessment services that compete with CSC across multiple service modules.
• AECOM: Global infrastructure consulting firm with substantial environmental services practice covering site assessment, industrial hygiene, and regulatory compliance for large enterprise and government clients — broader incumbent offering overlapping capabilities.
• J.S. Held: Global consulting firm combining technical, scientific, financial, and strategic expertise; acquired CSC in May 2026 to expand West Coast EHS capabilities for insurance claims, disputes, and catastrophe response — now the parent and a broad incumbent platform peer.
• ERM (Environmental Resources Management): Largest pure-play global environmental, health, safety, and sustainability consultancy, providing EHS consulting, site assessment, and compliance services — broader incumbent competing for large enterprise and insurance engagements.

Direct peers

• Roux Associates: Environmental consulting firm specializing in site investigation, remediation, regulatory compliance, and litigation support for industrial, legal, and insurance clients — a strong peer on the litigation support / expert witness dimension.
• Apex Companies: National environmental consulting and field services firm providing industrial hygiene, environmental site assessments, indoor air quality, and compliance services — directly competes with CSC across core EHS service lines.
• Haley & Aldrich: Environmental and geotechnical engineering consultancy delivering site investigation, remediation, industrial hygiene, and building sciences services to commercial, institutional, and legal clients — closely aligned with CSC's technical EHS offering.
• TRC Companies: Publicly traded environmental and engineering consulting firm delivering EHS services, site assessments, air quality, and regulatory compliance to industrial, utility, and government clients — a comparable integrated EHS services peer.
• Terracon Consultants: Large US employee-owned environmental, geotechnical, and facilities consulting firm offering site assessments, industrial hygiene, asbestos/lead surveys, and litigation support — directly overlapping CSC's core service portfolio at greater scale and national footprint.
• Montrose Environmental Group: Environmental services company providing air quality, environmental testing, site assessment, and advisory services with litigation/expert support — directly comparable to CSC across industrial hygiene, environmental testing, and expert services.

Market position

Strengths5 records

Weaknesses4 records

Competitive moat4 records

Key risks6 records

Key highlights7 records

Customer concentration

• Xx.com/ClarkSeifClark

Revenue estimate

Valuation estimate

Number of profiles

Profiles7 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about CSC