By Richard L. Gaw 
Staff Writer 

During the summer of 2022, in response to a rising number of complaints by area residents about the effect that the odors emitted from nearby mushroom composting facilities were having on their health and their household appliances, New Garden Township partnered with Dr. Lorenzo Cena, Ph.D., M.S., the Director of Environmental Health Program and Associate Professor at West Chester University to commission a one-year study from February 2023 to February 2024. The study’s intention was to measure the air quality near these mushroom farms; specifically, whether ammonia, methane and Hydrogen Sulfide met or exceeded acceptable levels as determined by the Pennsylvania Department of Environmental Protection (DEP).

On Sept. 4, before an overflow audience of area residents, Cena shared the study’s findings that revealed that Hydrogen Sulfide levels were 33 times higher than the recommended levels established by the DEP for the general public, who specifies that concentrations of the gas over the course of one hour should not exceed 0.1 ppm, (parts per million) and that concentrations over a 24-hour period should not exceed 0.005 ppm.

In contrast, the National Institute of Occupational Health and Safety recommends occupational levels not to exceed 10 ppm and an exposure time to not exceed 10 minutes. In addition, the Occupational Safety and Health Administration (OSHA) permits concentrations of up to 20 ppm in the workplace.

As he introduced his presentation, Cena provided a summary of what exposure to various levels of Hydrogen Sulfide has on those who are exposed to it. Low concentrations – from 0 ppm to 10 ppm – create a strong odor of rotten eggs and cause irritation of the eyes and the respiratory system. Elevated concentrations – from 10 to 50 ppm – may cause dizziness, nausea and headaches, and for those who are exposed to levels of 50 ppm and higher, they may be susceptible to severe respiratory irritation, convulsions, a loss of smell to detect gas, coma and immediate death.

The study, which was conducted by Cena and graduate students from WCU, involved the tracking of Hydrogen Sulfide, ammonia and methane levels using three G7 XO area monitors that were positioned between 100 to 600 feet away from mushroom composting sites in the township. While ammonia and methane levels measured in the study were found to be barely detectable and pose no health risk in these areas, one monitor showed significant spikes of Hydrogen Sulfide levels over the year. 

At location A, the highest concentrations were detected in November and December of 2023, which went as high as 6.5 ppm, well above the DEP’s 0.1 ppm recommendation. The study further showed that on one day in May of 2023, Hydrogen Sulfide levels were 4 ppm and during early July of last year, levels registered at nearly 4.5 ppm.

The study also revealed that the highest concentrations of Hydrogen Sulfide were detected on Mondays and Wednesdays and that the highest percentage of peaks occurred from midnight to 8 a.m.

‘Erratic’ readings at one location

While the Location B monitor registered levels that did not exceed recommended levels of Hydrogen Sulfide, the Location C monitor measured what Cena called “erratic readings” that yielded readings at or more than 100 ppm in November of 2023. He later said that the reading was inaccurate and that “instruments can have faults and have readings that are erratic and need validation,” he said. 

The Location B monitor was not calculated in the final study findings, he said.

From the start of what has become one of the top concerns and news stories in New Garden Township, the echo of residents’ complaints to the township and elected officials have focused not just on their exposure to Hydrogen Sulfide, but the corrosive impact that the gas has had on their household appliances, some of which have had to be replaced repeatedly. Cena said that the study also fell victim to the very gas whose levels were being monitored. Within a year of the study, various rods and bolts on the monitors were severely corroded.

Cena’s concluding remarks called out the need to identify “point sources and tasks” to lessen potentially harmful Hydrogen Sulfide levels at composting plants throughout Chester County as part of a collaboration between researchers, local governments, mushroom operators, as well as the Avondale-based American Mushroom Institute. 

Cena said that he is currently applying for a grant from the Pa. Department of Agriculture for a two-year study intended to develop what he called “a larger-scale study” that would install ten monitors that will be able to detect higher concentrations of gases. 

Mushroom industry introducing nine-month mitigation study

Following Cena’s study results, American Mushroom Institute (AMI) President Rachel Roberts introduced a nine-month Mushroom Farm Compost Hydrogen Sulfide Mitigation Pilot study the agency has recently begun. In her presentation, Roberts said that the initiative for the project stemmed from phone calls she received from industry representatives in 2021, who began expressing the displeasure of nearby residents who told them about the effects the odorous effects of composting practices were having on their health and their home appliances. 

In partnership with the Director of the Mushroom Research Center at Penn State, AMI is overseeing the installation of six MultiRae gas monitors and a weather station that captures and calculates Hydrogen Sulfide levels near emission locations at an undisclosed Chester County Farm.

The study will also oversee a mitigation practice that will involve the application of carbon activated tarps over wastewater “lagoons” to see if they lessen levels of Hydrogen Sulfide. 

“This is something that is currently in the marketplace that is being implemented on other types of farms,” Roberts told the audience. “The belief of the folks we’re working with is that this may be something that the mushroom industry can respond to and address.

“We’re here to react and respond to some of this good information that we’re getting. We have the DEP’s information. We’re learning about this in real time with you tonight about what this actual data is, and we want to assure you that our businesses who are sustainable are good neighbors. We know that we have to address these concerns and respond to the recommendations we get based on the information. 

“We want to know what it is and what to do.” 

Comparisons to Pa. DEP study results

The Sept. 4 presentation served as a comparison to the results of an air quality study town hall meeting on March 21 that brought together an overflow audience of area residents, elected officials and state experts in the areas of health, agriculture and the environment to the New Garden Township Building. The air quality 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.

Introduced by Dr. Julie Miller, a public health toxicologist with the Pennsylvania Department of Health (PADOH), the report measured the Hydrogen Sulfide levels at 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 ppm 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 ppm over the odor threshold. The study also said that 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 exposure to Hydrogen Sulfide can lead to headaches, poor memory, tiredness and difficulty with balance and a possible loss of consciousness, Miller told the audience, “Being exposed to a chemical doesn’t mean that you’re going to get sick. 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 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?” 

The PADOH later recommended at the meeting 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.

Questions and answers

During the question-and-answer portion of the meeting, Roberts said that gathering and analyzing the data from the pilot study is expected to take a year to 18 months before it is completed. She said that if the results of the study clearly indicate that the application of tarps over wastewater lagoons lessen the levels of Hydrogen Sulfide, there is a strong potential that the process will be embraced by the local mushroom industry.

“There is a high probability that the industry will do this voluntarily,” she said. “They are very concerned about this concern, and they want to learn what they can do, ideally to make it go away but at the minimum to make the community livable for everybody. 

“We are learning with all of you as this unfolds. We haven’t been asked a lot of these questions before. We haven’t been asked whether or not we have a solution to have a solution to a problem, and it hasn’t been presented before as a scientific problem.”

Several of the residents in the audience took offense to AMI’s pilot study, saying that what has become an issue of health in New Garden Township continues to be pushed down the road in the favor of additional research as opposed to tending to the immediate need of repairing the air quality at the composting sites.

“We continue to do study after study, when all it really takes is the state to finally get a grasp on this,” said 24-year Landenberg Hunt resident Ron Lupo. “This is a chemical going into the air. If this were a factory or an industry, they would be restricted about what to put in the air. 

“All it takes is an act of law, to regulate the mushroom industry to live by the same standards that other industries do,” Lupo added. “I don’t think it’s fair for industries to have to go all that they go through, when you give the mushroom industry free reign, and that is wrong. That is very wrong.”

At one point during the question-and-answer session, former township resident Emily Carroll told Roberts that after inhaling and living with the gaseous fumes from area composting functions, she had to move from her parents’ house in Landenberg Hunt, where they have lived for 34 years.

“This is unacceptable,” she told Roberts. “My parents are probably going to die. The majority of these people are a lot older than me, so what are you trying to tell me -- that I can’t bring my kids to my own parents’ house because of the smell? Figure it out.”

Roberts reinforced to those in attendance that the mushroom industry is committed to exploring possible mitigation efforts in an effort to draw Hydrogen Sulfide levels down to acceptable safety standards.

“Everything we are doing is a good faith effort to understand what we can and to implement what could be a better result,” she said. “If we could wave a magic wand, we would do it today, but we’re just trying to resolve the issue.”

Cena said that he and his students will be collaborating with AMI on the agency’s study, while keeping its respective studies separate from one another. The goal, he said, will be to find the source of the problem that is causing these spikes to appear in readings, and the best way to do that will involve sharing the goal with Chester County mushroom farmers, whom he recently met with. 

“Once we find it, can we isolate it?” he said. “Can we change and modify the process, so that the concentration of [Hydrogen Sulfide] can be kept low? Rachel was able to gather the farmers around the table and I told them, ‘As we are analyzing the data, we’re finding out that we think there is a problem. If you want to be a good neighbor, you will allow us to come to your farm and take samples, and what we can do is provide you with independent data that you can compare with your data and help you validate what you’re looking at.

“With their instruments and our instruments, it can give us more information, and that’s what we want. More data is always better than less data.”

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