ANSI/NSI 373 Sustainable Stone

1. Review the Standard: Download and study the ANSI/NSI 373 Sustainable Stone Standard document, available through the Natural Stone Institute. Familiarize yourself with the environmental, social, and economic criteria your operations will be evaluated against.

1. Conduct a Gap Analysis: Compare your current quarrying and/or fabrication practices against the ANSI/NSI 373 requirements. Identify areas where your operations fall short of the standard's thresholds for energy use, water management, waste, worker safety, and human rights.

1. Implement Improvements: Address gaps identified in your analysis. This may involve updating environmental management procedures, improving worker health and safety programs, documenting supply chain practices, and establishing measurement systems for key performance indicators.

1. Compile Documentation: Gather and organize all required records, including energy consumption data, water use logs, waste management records, worker welfare policies, and any relevant environmental permits or certifications.

1. Select an Accredited Certification Body: Contact the Natural Stone Institute or an ANSI-accredited third-party certification body authorized to conduct ANSI/NSI 373 audits. Request a quote and schedule your audit.

1. Undergo the Third-Party Audit: An accredited auditor will review your documentation and conduct an on-site inspection of your quarry and/or fabrication facility. Be prepared to demonstrate compliance across all standard criteria and answer auditor questions.

1. Address Non-Conformances: If the auditor identifies any non-conformances, you will typically have an opportunity to correct minor issues before a final certification decision is made.

1. Receive Certification and Use the Label: Upon successful audit, you will receive the ANSI/NSI 373 certificate and be listed in the Natural Stone Institute's online registry. You may then use the certified product label on marketing materials and product documentation.

The ANSI/NSI 373 standard evaluates natural stone operations across three primary sustainability pillars: environmental, social, and economic. Each pillar contains specific criteria that quarries and fabricators must meet or demonstrate measurable progress toward.

Environmental Criteria cover the most extensive set of requirements, including energy consumption and efficiency measures, greenhouse gas emissions tracking, water use and conservation practices, waste generation and diversion rates, land use and reclamation planning at quarry sites, and management of hazardous materials. Operations must demonstrate active monitoring and improvement programs in these areas.

Social Criteria address the treatment of workers and surrounding communities. This includes compliance with applicable labor laws, worker health and safety programs (including silica dust exposure management), fair wages and working hours, prohibition of child and forced labor, and community engagement practices. Human rights due diligence across the supply chain is also evaluated.

Economic Criteria examine the long-term viability and responsible governance of the business, including ethical business practices, supply chain transparency, and local economic contributions. Companies must demonstrate that their operations support sustainable livelihoods and responsible sourcing.

The standard uses a combination of required baseline criteria (which must be met for certification) and performance-based criteria (where companies earn points or demonstrate continuous improvement). Both quarrying operations and fabrication/processing facilities can be certified independently or together, allowing companies to certify the portion of the supply chain they control.

ANSI/NSI 373 is the primary sustainability certification specific to the natural stone industry in North America and is increasingly recognized internationally. It was developed to fill a gap left by generic environmental management standards, which did not address the unique sustainability challenges of stone quarrying and fabrication. The certification is particularly valued in the commercial construction and architecture sectors, where specifiers increasingly require documented sustainability credentials for materials used in LEED, WELL, and other green building projects.

Adoption remains relatively niche compared to broader certifications like ISO 14001 or Cradle to Cradle, reflecting the specialized nature of the natural stone industry itself. The Natural Stone Institute estimates that certified companies represent a growing but still modest share of the global stone supply chain. Demand is driven primarily by North American and European markets, where green building standards and sustainable procurement policies are most mature. The program has gained traction as LEED v4 and v4.1 increased scrutiny of material sourcing and transparency.

The competitive landscape includes Environmental Product Declarations (EPDs), which are increasingly required alongside or instead of process-based certifications, and the Declare label from the Living Future Institute. The Natural Stone Institute has actively worked to align ANSI/NSI 373 with LEED credit pathways and has developed an industry-wide EPD to complement the standard. Growing regulatory attention to silica dust exposure and supply chain human rights due diligence (particularly in the EU) is likely to increase the relevance and demand for ANSI/NSI 373 certification in the coming years.

The ANSI/NSI 373 Sustainable Stone Standard was developed by the Natural Stone Institute (NSI), an organization formed from the merger of the Marble Institute of America (MIA) and the Building Stone Institute (BSI) in 2015. The standard itself was first published in 2013 under the auspices of the then-separate MIA, with the designation reflecting its ANSI accreditation — a mark of rigorous, consensus-based standard development. It was created in response to growing demand from architects, specifiers, and construction clients for a credible, third-party-verified sustainability framework specific to natural stone, as existing standards did not adequately address the industry's unique environmental and social challenges.

Since its initial publication, the standard has undergone revisions to strengthen its criteria and align with evolving green building frameworks, including LEED v4. The Natural Stone Institute has continued to invest in the program's development, including the creation of an industry-wide Environmental Product Declaration (EPD) for natural stone to complement the standard. In 2026, the Natural Stone Alliance provided grant funding to support ongoing sustainability initiatives, including advancement of the Natural Stone Sustainability Standard, signaling continued industry commitment to the program's evolution.