West Haven Announces Resolution To ‘Mysterious Hum’ Noise Issue In Neighborhoods

WEST HAVEN, CT — (From City of West Haven): The city released findings on Thursday from an acoustic study identifying a source of noise complaints in the residential area surrounding Heffernan Drive and outlining corrective actions being taken.

Initial testing conducted by city Health and Human Resources Commissioner John M. Carrano using a handheld noise meter indicated potential violations for the state statute related to allowable noise; however, more advanced monitoring equipment was necessary to accurately measure and analyze the sound levels.

Therefore, an acoustic engineer was hired to perform testing at a professionally higher level as the city is legally required to have the data to address the source of the noise.

In January 2026, the city retained Acoustic Technology LLC of Waterford to perform the detailed study, analyze the data and deliver a final report. Due to two significant snowstorms, however, fieldwork was delayed until late March and continued through April, with the final report issued in May.

Acoustic Technology took readings at more than 10 locations throughout the surrounding residential neighborhoods. Measurements indicated that noise levels at five monitoring locations may exceed applicable thresholds under certain conditions, primarily at locations adjacent to the industrial zone boundary. Readings at residential locations not immediately adjacent to the industrial zone did not exceed applicable standards.

The study identified a prominent and discrete tone. A prominent and discrete tone is a measurable criteria in the noise statute, and its measurement reduces the allowable noise levels by 5 decibels to 46 decibels at night for noise traveling from an industrial zone into a residential zone. It was confirmed that the prominent and discrete tone emanates from equipment at Glanbia’s facility on Heffernan Drive.

City officials promptly shared the study results with Glanbia, including specific days and hours when elevated readings were identified.

The data enabled the company to review production logs and isolate the source. Glanbia subsequently engaged its own acoustics engineers, who determined that the existing roof-mounted silencers, or mufflers, replaced in 2024, are insufficient for the particular tone generated by the equipment.

Glanbia has already initiated the procurement and installation of custom silencers, a process targeted for completion by late September. Mayor Dorinda Borer required the company to develop an interim solution. In turn, the company purchased and installed temporary muffler blankets and U-bends to mitigate sound levels until the permanent solution is implemented.

During the first two weeks of the temporary solution, the city has monitored the noise levels, and the decibel readings have all been within the allowable range. Additionally, as part of its cooperation with West Haven, Glanbia has agreed to reimburse the city for the cost of the acoustic study.

“Once presented with the official sound study results, Glanbia has been cooperative and has worked to put a temporary resolution in place that brings the levels down, and has pledged to permanently correct the problem,” Borer said. “We will continue to monitor the temporary solution to ensure that readings remain below ordinance levels and to ensure full compliance with the permanent solution.”