AYER -- The neighborhood on the uphill side of Westford Road is the type of place where it is easy to imagine folks outside mowing the lawn or having a barbecue.
But in the industrial area on the other side of the road creates unwelcome odors described as acrid, noxious and nauseating.
For people living upwind of Nasoya Foods the smells they say last up to a week mean no grilling or yard work.
Janet Williams lives less than a quarter of a mile from the plant as the crow flies.
"It's atrocious," the Mulberry Circle homeowner said. A daycare provider, she has to go inside and shut her windows when it gets too strong.
Another resident, Don Osmer, took his concerns to the selectmen and the Board of Health. He has lived on Mulberry Circle for 13 years and the past year has been the worst, he said in a phone conversation.
"I'm vocal because it's really bad," he said. When he smells the odor, which sticks to clothing, he notifies both the Massachusetts Department of Environmental Protection and the Board of Health.
Osmer has gone to meetings of both the Board of Health and the Board of Selectmen. He praised the efforts of both boards for trying to end the problem. "They've been phenomenal," he said.
However, nothing has improved as far as he can tell. He blames the inaction on MassDEP.
Confirming the odors when they are reported is a job for Bridgette Braley, district sanitarian for the Nashoba Associated Boards of Health.
Enforcement is the job of MassDEP she said.
"It really is a quality of life issue," said Town Administrator Robert Pontbriand in a phone conversation. Neighbors and selectmen are getting frustrated with the continuing smells.
Since August Nasoya representatives, residents and town officials have met to discuss the problem.
The smell has been a problem for years, said Selectman Chris Hillman. "Do you guys know what the hell you're doing with this?" he said to company representatives during a meeting on Oct. 3.
Both he and Selectman Gary Luca said during the meeting that they would like to shut the plant down.
"Nasoya does not deny there is a problem," Pontbriand said. "They've taken full responsibility for it and they're committed to resolving it."
Their solution will cost around $300,000, he said.
The company has a plan in place to add an air scrubber to use when the two existing units are overloaded with a sudden change, said Elvin Moquete, an engineering project manager for Nasoya during the Oct. 3 meeting. Nasoya is gathering data which includes times when sludge trucks load and has consultants to ensure the solution will work.
The consultants were chosen from a list provided by MassDEP at Nasoya's request, he said. They will include historic and wind data in their studies.
"We don't want to repeat this vicious cycle," Moquete said.
New sensors are installed and testing is ongoing, according to a slide presented at the Oct. 3 meeting. The new air scrubber is scheduled to go online at the end of November.
The Ayer odor complaints have reached the corporate level.
"We're very, very aware of the issue," said Ross Gatta, CEO of Nasoya Foods USA in a phone call. "We take it serious."
"We are working hard to find a solution," he said. "We are ready to invest in that solution."
The smells, which can last between a couple of hours and a couple of days occur in abnormal situations, he said.
In one recent incident, excessive cleaning of equipment in the factory led to unusual smells going through the air-handling system in the wastewater treatment plant. The existing air scrubbers could not handle it.
"A high-cleaning regime can mess with the organisms," Gatta said.
The cleaning system is biodynamic, he said. One of the byproducts of cooking soy and separating the liquids is hydrogen sulfide. Usually the two air scrubbers can handle it.
In another, an employee inadvertently failed to follow strict protocols, he said. The employee was retrained.
"Clearly when we have some of these unusual events, we can get overwhelmed," he said. "Murphy's Law: You can't predict when anything's going to go wrong."
Funds for the new scrubber have been approved, he said. Nasoya is waiting for final designs from a contractor and state Department of Environmental Protection input.
"They're pretty tough on us in terms of making sure we're doing the right thing," Gatta said.
"We want to make doubly sure that it's the right approach to resolve it once and for all," he said. "We owe it to the town and our neighbors."
Some see a lack of involvement by MassDEP as a problem.
The state agency was on site at Nasoya at the end of August, Pontbriand said. Mary Jude Pigsley, the regional director is scheduled to be at the Oct. 17 meeting, he said. He expects her to discuss what role the DEP plays in enforcement.
There are limited local options to enforce odor control. Like most municipalities, the town does not have a bylaw that addresses odors, Pontbriand said.
Twice in the past, the plant was placed under a consent decree and fined by the state agency.
In 2007, VitaSoy was fined $12,000 for air pollution and industrial wastewater treatment violations. Odor complaints resulted in a $10,995 penalty in 2013.
Nasoya was one of the key brands of VitaSoy when Pulmuone Foods USA purchased part of VitaSoy's holdings in May 2016, Gatta said. The new holdings were renamed Nasoya Foods USA. Global headquarters are in South Korea.
After Nasoya opened its new wastewater treatment plant, the Department of Public Works had no more issues with the water quality the plant discharged into the municipal system, said Superintendent Mark Wetzel.
He had not experienced the recent odors, but said the "water guys" sometimes commented on them when they returned.
The new wastewater treatment plant was installed in 2013, Pontbriand said.
Nasoya employs 220 workers covering two shifts for six days a week, Gatta said. It is closed at night and on Sunday, but in periods of high demand can add a third shift and Sunday hours.
The location has been used for food processing for many decades.
VitaSoy purchased the plant in December 1996 from the New England Shrimp Company, according to the assessor's records.
The owner and the plant manager of New England Shrimp Company were convicted and imprisoned after an investigation into adulterated shrimp. Between 1988 through June 1992, the company added chemicals to change the appearance and increase the weight of the shrimp, according to a 1995 PR Newswire release. They sold the imported catch as pink shrimp from the United States.
The court found the company, which sold $146 million worth of adulterated shrimp, did not have sufficient assets to pay a substantial fine.
When New England Shrimp was in business, the Mulberry Circle neighborhood which is affected by the odor from Nasoya had not been built.
Crabtree Development purchased land across Westford Road from the plant in 1993 and began building houses. Some are still occupied by the original purchasers like the Williams family.
Follow Anne O'Connor on Twitter @a1oconnor.