Noise, PFAS and heat‑island worries frame Project Tango debate as experts disagree on evidence

A central thread of the Project Tango hearing in Palm Beach County was technical disagreement about operational noise, environmental effects and how the county will enforce limits if the project is built. Commissioners repeatedly pressed applicant experts and county staff for specifics on measurement, monitoring and long‑term verification.

Acoustical experts explained that modeling uses octave‑band analysis (Hertz) and weightings such as A‑weighted (dBA) and C‑weighted/DB‑C metrics for low‑frequency concerns. Mark Bastach, an acoustical witness for the applicant, said the project’s worst‑case modeled levels would be below the county night standard at the property line. Staff clarified that a required final sound study must be completed after equipment selection and before construction, and that recorded measurements would be taken along the property line at maximum 400‑foot intervals over 24‑hour periods; an annual noise and vibration study is also required from the date of first certificate of occupancy.

Opponents and several commissioners said modeled compliance does not settle questions about low‑frequency propagation, potential effects on animals (notably equestrian operations near Arden) and the ability to verify compliance over years if equipment changes. Commissioners asked whether fans and cooling systems could become louder with age; applicant and acoustical witnesses said predictive maintenance and sensors can detect and enable rectification of abnormal conditions, and that noncompliant operations could be required to shut down.

Public‑health witness Robert McCunney, M.D., told the board he found no peer‑reviewed epidemiological studies specifically linking data‑center noise to chronic vascular disease; he said available literature treats noise as a dose‑dependent hazard and that, based on the modeling presented, he did not expect severe chronic outcomes for neighbors. He recommended occupational monitoring for employees consistent with OSHA/NIOSH standards.

Environmental concerns about coolant wastewater and PFAS were resolved in the hearing record by a clear county condition: Palm Beach County Water Utility Director Ali Bayard stated the county will not accept cooling wastewater into its sanitary sewer system; the applicant must haul any generated wastewater off‑site to an industrial wastewater treatment facility and provide the receiving facility’s permit and identifying information. Staff read conditions requiring interior floor drains for data‑center operations to be independent of the county sanitary system and containment tanks sized to 125% of the largest isolatable section.

The board also considered an emerging body of work on data‑center 'heat islands.' A public witness cited a preprint (Marioni et al., University of Cambridge) reporting land‑surface temperature increases near large facilities; county and applicant experts questioned methodology and emphasized that the preprint had not undergone peer review and that evidence remains contested.

Taken together, the technical disagreements over low‑frequency noise, uncertainty about long‑term monitoring and broader environmental questions helped inform commissioners’ judgment about compatibility with the Arden community and contributed to the eventual denial of the application without prejudice. Staff will incorporate the board's findings into administrative reviews of pending applications and provide a follow‑up report.