Under standard conditions of the contract used in CDT (e.g., AIA A201 as referenced by CSI), when hazardous materials or unsafe conditions are encountered:
The Contractor is required to stop work in the affected area and notify the Owner and Architect/Engineer.
The Contractor must not proceed until the hazardous condition has been evaluated and remedied by the Owner with qualified professionals.
CSI’s project delivery materials emphasize that the contractor is responsible for means, methods, and safety of construction operations. That includes the authority—indeed the obligation—to stop work where hazardous substances or conditions present an imminent danger to workers.
Why the others are incorrect:
A. Architect/engineer – The A/E can recommend suspension of work for nonconforming work or other reasons, but the specific duty and right to stop work because of hazardous conditions in the field lies with the Contractor under typical general conditions.
C. Stakeholders – This is a generic term, not a contract party with defined authority in CSI’s framework.
D. Facility manager – The facility manager may be involved if the existing facility is affected, but is not the contract party empowered in the construction contract to stop the contractor’s work.
Relevant CSI references (no links):
CSI Project Delivery Practice Guide – chapters on Construction Phase responsibilities and safety.
CSI CDT Body of Knowledge – discussion of contractor responsibilities and hazardous materials clauses in standard general conditions.
