ASML has responded to neighborhood complaints of construction noise by identifying the source of the pounding and announcing a point at which it will end. It has also offered neighbors a choice of whether they prefer a long construction period or a shorter one with earlier starts in the morning.

Rock removal through hammering and chipping is the only option, the company said. Blasting is not possible due to the sensitive manufacturing equipment on the campus at 77 Danbury Road, according to Peter W. Rader, vice president of Jones Lang LaSalle, the Stamford-based project developer for the parking garage being built on the ASML property. It is likely this hammering is what neighbors are complaining about, he said in a memo to company officials released by ASML’s attorney, Casey Healy.

The construction manager responded by saying the hammering will be complete by July 3.

The team discussed pushing off the start of the rock removal by an hour each day, but that would mean the work continues to July 9 because of the hard granite rock.

Healy reached out to neighbors for their preference, but a response has not been released. Healy also told the neighbors in a letter the project professionals concluded it is not feasible to build a barrier that would block the “line of sight” for noise at the construction zone.  

Neighbors of ASML, which is undergoing a $100-million expansion at the facility on Danbury Road, first began complaining to town officials about noise from the construction last month.

The construction noise became a topic of concern for the Planning and Zoning Commission because ASML has applied for an increase in site coverage for its Design Enterprise zone, from 40% to 50%, to better accommodate the company’s growth. The expansion is expected to create 500 new engineering and manufacturing jobs.

The company also applied for construction of a 25,170-square-foot addition on the southwest corner of the existing facility at 77 Danbury Road, to be used as a truck loading dock.

Planning and zoning commissioners and staff assured the outraged neighbors regulations on noise levels will be followed.

First Selectwoman Lynne Vanderslice, who attended the meeting to address the neighbors’ concerns, called the company’s management to work out a solution.

The expansion includes a 700-space parking garage on what was a former parking lot and office and manufacturing areas that will add more than 45,000 square feet of work space across three floors.