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Chester County Press

Local air quality study yields facts, potential solutions and resident ire

03/27/2024 12:01PM ● By Richard Gaw

An overflow audience of area residents, elected officials and state experts in the areas of health, agriculture and the environment gathered at the New Garden Township Building on March 21 for a two-and-a-half hour-long forum that combined data and ideas with several years of residents’ frustration, under the large umbrella of an air quality study that evaluated the levels of Hydrogen Sulfide in New Garden and London Grove townships.

The study, conducted by the Pennsylvania Department of Health’s Division of Environmental Health Epidemiology, evaluated levels of Hydrogen Sulfide in New Garden and London Grove townships from Aug. 2021 to Dec. 2022 that was collected by the Pennsylvania Department of Environmental Protection’s (DEP)’s Bureau of Air Quality. The town hall meeting also invited representatives from the Pa. Department of Agriculture (PADOA) and the DEP.

The study was requested by State Rep. Christina Sappey in response to her receiving complaints from several members in her constituency who have reported a glut of persistent health conditions from the Hydrogen Sulfide odors in their neighborhoods, as well as shared the impact that the gas has had on their corroding household appliances. 

While the survey results and the ensuing comments from residents did not place the mushroom industry on trial, it did serve to train its focus on the industry itself, given the overwhelming evidence that supports the fact that the source of these high levels of Hydrogen Sulfide are emanating from nearby mushroom growing facilities, as part of a Chester County industry that is responsible for nearly two-thirds of all mushroom production in the U.S., and whose epicenter of business falls in New Garden and London Grove townships. 

As stated in the PADOH report’s “Site Background and Community Concerns,” the mushroom growing process involves creating a substrate and compost favorable to mushrooms that compete against fungi and bacteria. Mushrooms are grown indoors and require nutrient-rich substrate to grow, and while the contents of the substrate are up to the farmer, common ingredients found in substrate include a mixture of corncobs, hay, straw, straw-bedded horse manure and poultry manure. 

As a result, the report stated, the composting process allows for favorable bacteria to grow and reproduce that during the process create anaerobic conditions such as the presence of Hydrogen Sulfide and other sulfur compounds that give off the gaseous odors, similar to that of rotten eggs. 

Three air monitors

The results of the 56-page report were introduced by Dr. Julie Miller, a public health toxicologist with the Pennsylvania Department of Health (PADOH), who said that to gauge the levels of Hydrogen Sulfide in the area, the agency set up three air monitors in the area: the “West Grove Monitor” at the Avon Grove Charter School; the “Landenberg Monitor” at the New Garden Township Building; and the “New Garden Airport” monitor at the New Garden Flying Field.

Using standard Public Health Assessment methods developed by the federal Agency for Toxic Substance and Disease Registry, the PADOH concluded that:

  • the highest hourly levels of Hydrogen Sulfide may have led to short-term (acute) respiratory effects in “certain individuals” in Landenberg and West Grove; specifically, those who have respiratory conditions like asthma. Further, the results concluded that on certain hours and days, hourly Hydrogen Sulfide odors that can negatively impact those with asthma;
  • that longer exposure to Hydrogen Sulfide is “unlikely” to lead to long-term health effects, and that when averaged over a longer period, the levels were lower than levels where long-term effects might occur; and that
  • Hydrogen Sulfide levels were above common thresholds of 8 parts per billion (ppb) that could lead to headaches, nausea, fatigue and stress in some residents. Further, 28 percent of the hours monitored were above the odor thresholds, and 13 percent of the hours monitored were 30 ppb over the odor threshold. The highest Hydrogen Sulfide levels at the West Grove and Landenberg monitors were reported to most occur on Tuesdays and Fridays and were highest during the evening and early-morning hours of fall months. 


While Miller said that exposure to Hydrogen Sulfide has not been shown to cause cancer in humans, the effects from low-level exposure can range from irritation to the eyes, nose and throat to headaches, poor memory, tiredness and difficulty with balance. Exposure to very high levels of Hydrogen Sulfide can cause loss of consciousness. 

“Being exposed to a chemical doesn’t mean that you’re going to get sick,” Miller said. “The Department of Health evaluates the potential risk to health, so based on the levels that we see and who is exposed, is there a more-or-less likelihood that you may be experiencing health effects related to that chemical? Whether or not someone gets sick from a chemical depends on many different factors. This could be the chemical’s properties, the levels that are in the environment, how you are exposed, whether or not you are eating it or drinking it or inhaling it…and the length and frequency of the exposure, so are you exposed over a short period of time, or over a day or a year?

“Longer term health effects are unlikely, but we have to admit that sometimes more research needs to be done to understand the health effects in people who have low-level exposure to Hydrogen Sulfide gas in the general population.”

The PADOH recommended that mushroom-growing facilities suspected of high levels of Hydrogen Sulfide “engage in best practices and engineering controls” to reduce odors; enact efforts to significantly reduce levels and/or ensure that Hydrogen Sulfide emissions are located away from residential areas to protect public health; that facilities and their community partners consider outdoor air monitoring to see if odor and health effect levels are being exceeded in nearby homes and business; and that residents “remain indoors when outdoor odors are ‘bothersome’ and leave the area for a few hours, if possible,” and consult their physicians if they are experiencing health issues.

$1.5 million in research funding

Doug Wolfgang, the executive secretary for PADOA’s State Conservation Commission, acknowledged the health and environmental impact of Hydrogen Sulfide levels on area residents.

He told the audience that he recently asked the Commission to approve $1.5 million in research funding that will be available for institutions to conduct research on the topic of Hydrogen Sulfide coming from the agricultural industry.

“We believe that’s the first step -- researching this to identify clearly where the source of the gas is coming from – the compost piles, the substrate, the lagoons -- and what those levels are for each of those different locations and areas,” he said. “Step two will be to identify the best practices to mitigate the effects of [Hydrogen Sulfide] and to find out what is feasible for Pennsylvania. 

“Third, we will provide the technical and financial assistance that will be necessary for farmers to install the types of practices that will mitigate [Hydrogen Sulfide emissions].” 

Wolfgang also expressed the need for long-term monitoring to ensure that the community needs are met.

“Businesses who are affected by this are very concerned and want to work with us to identify what those practices are,” he said. “The mushroom industry in Pennsylvania is a huge sector of our agricultural economy and that is something we take very seriously along with our concern for the public’s health. Finding that balance and being able to do some meaningful mitigation strategies is very high on our priority list right now.”

Wolfgang said that the State Conservation Commission’s immediate intention is to identify the farms that have the greatest needs, and that the agency may be able to get signed contracts to begin research by the end of the current fiscal year. 

‘Plume of Doom’

While the first 45 minutes of the meeting yielded statistics and solutions that may ultimately lead to lower Hydrogen Sulfide rates in New Garden and London Grove townships, the remaining segment served as a one-hour-and-forty-five-minute testimony from more than 25 area homeowners and employees, who from the start of their comments, let it be clear where the target of their pent-up anger and frustration was directed at.

Landenberg Hunt resident Ron Lupo invited the agency representatives to his house to witness first-hand the consistent odor he and his family endure. 

“We are trying to be good neighbors, and all we’re asking is for reciprocation,” he said, referring to photographs of several appliances and exterior utility boxes he displayed for the representatives, that have been severely corroded due to exposure to Hydrogen Sulfide throughout the development. “You’re going to talk to me about my health when it’s doing this to that?” he continued, referring to the photographs. “That is the Plume of Doom in our neighborhood. None of you live in this neighborhood, because if you did, you would be fighting faster than you are now.”

One 23-year resident of the Landenberg Hunt development called for the movement of the three monitors to locations that are closer to the mushroom composting farms, that she said will be able to provide more accurate readings of Hydrogen Sulfide.
“There have been certain deep smells to the point where I cannot stay at the bus stop with my kids,” she told the representatives. “I can see the white smoke in the middle of the night, and when I call the police, they give me the response of ‘It’s the mushroom farms. They have the money to pay the fines.’ 

“I don’t want to insult you, but [your report] felt like there was smoke coming my way. I don’t need that. I’ve had enough smoke over the last 20-something years. We have families and kids and grandkids, and we don’t even know what is possibly ahead of us because of this. Help us. That’s why you’re here. That’s why we pay you. That’s where our tax dollars are going. Do something. Please.”

Conclusions, solutions and calls for cooperation

Throughout the public comment portion of the meeting, elected officials and agency representatives continued to address the proverbial white elephant in the room: that positive environmental, agricultural, and legislative change to provide cleaner air and safer composting practices will require the full cooperation of the mushroom industry in the near- and long-term future.

Each of the agency representatives pledged to work in collaboration with Dr. Lorenzo Cena, associate professor in the Department of Public Health Sciences at West Chester University, who attended the meeting. Cena and a select number of his students are conducting an air quality study in New Garden Township, the results of which will be provided to the public when the study concludes.  

While Wolfgang said the Commission will look to partner with agencies like the USDA and the Chester County Conservation District, he said that the PADOA intends to pursue the same cooperation from the mushroom industry in order to bring possible solutions out from the pages of studies and into the best management practices at mushroom facilities.

“I wish I had a very firm answer [regarding getting the cooperation of the mushroom industry], other than that we will continue to work very closely with the industry and with our other agencies to do what is most reasonable and helps address the issue related to public health,” he said. “It’s absolutely a priority for us.” 

“My only commitment to you – that’s all I have, because I am a man of my word -- is that we will get to the bottom of this, we will partner with our friends in the mushroom factories and we will see what we can do to get this resolved,” State Sen. John Kane told the audience. “I understand your anger. I understand the questions you are asking about who is overseeing the mushroom companies. I assure you that I will bring those questions back to Harrisburg and try to get as many answers as I can.”

Referring to the agencies that attended the meeting, Sappey said, “They came to share the data that we asked for and it’s the beginning of how we will address this issue. My colleagues Sen. Kane and Sen. Carolyn Comitta and other representatives in the area care very much for what happens in the area, not just in New Garden but in the region, as well.”

The entire Pennsylvania Department of Environmental Protection report – and a summary -- can be found on the New Garden Township website,

To learn more about environmental odors, contact the Agency for Toxic Substances and Disease registry at

To contact Staff Writer Richard L. Gaw, email [email protected].