"Deafening." "Like a Jet Engine." "A Diesel Truck That Runs All The Time."

Spectra claims that this Compressor Station won't be a noise nuisance, but evidence from Compressor Stations around the country demonstrates otherwise. These facilities are noisy during normal operations, and deafening during the periodic blowdowns.

The operating "hum" of a 7,700 horsepower Compressor will be amplified as sound travels across the water and into North Weymouth and Quincy. Spectra claims it won't be above 55 decibels when measured at the edge of their property line, but a study of sound and vibration hasn't been done.

The promises made by Spectra during the proposal simply are not an accurate picture of the reality of Compressor Station noise, and their claims will not be enforced. The surrounding community will pay the price when it comes to their health, property values, and enjoyment of the outdoors.

Regulation of sound is ambiguous, and State DEP's continue to struggle with how to regulate and enforce. (Source)

The decibel level only measures loudness. But many other factors affect how noise is perceived—from its frequency, to the topography of the area, even the weather and wind speed on a particular day.
— NPR StateImpact
According to a World Health Organization assessment of research, excessive noise can
also increase risk of cognitive impairment in children, sleep disturbance, tinnitus, and
high levels of annoyance.
— World Health Organization.
Compressors are noisy, as can be the control valves which regulate gas flow through the pipeline at the source station, compressor stations, distribution hubs and metering stations.
Pipeline & Gas Journal

What Do Compressor Stations Really Sound Like To Their Neighbors?

Youtube is full of videos of Compressor Stations and their true impacts on the surrounding environment.

Argument: this will be quieted by the building

Spectra argues that the sound of the Compressor will be muffled by the enclosed building. While this may damper the sounds of normal operations, it will do nothing to minimize the deafening blasts of a Blowdown, as the Blowdown separator is located outside of the building. 

Enclosures around natural gas infrastructure also come with their own risks. As Pipeline & Gas Journal (an industry publication) has said:

Regulating stations can have buildings installed around the stations which can then provide acoustic noise reduction. However, these buildings present a safety risk as, when there are gas leaks, the gas can collect in the building and create hazards of either asphyxiation or explosion.
— Pipeline & Gas Journal