By Richard L. Gaw 
Staff Writer 

Reflective of the one-year findings he and his graduate students uncovered from February 2023 to February 2024, Lorenzo Cena Ph.D., M.S., the director of Environmental Health and associate professor at West Chester University, delivered his final air quality study for New Garden Township to the township’s Board of Supervisors on Jan. 8.

The entire 83-page report – which is available on the township’s website: www.newgarden.org. -- measured ammonia, methane and Hydrogen Sulfide (H2S) emissions from outdoor fresh mushroom production (FMP) facilities throughout the township in order to determine whether they achieved acceptable levels as established by the Pennsylvania Department of Environmental Protection (DEP).

The study was in response to the township receiving several complaints by its residents over the past years regarding the persistent odors that regularly permeate from the township’s mushroom composting plants, their concern for what the effect of these gases have on their overall health and the extent to which hydrogen sulfide levels were damaging their household appliances. 

In the introduction to the report, Cena wrote that his study served to break ground on a little-researched topic.

“Residents in New Garden Township and surrounding fresh mushroom production (FMP) facilities have lodged complaints about the rise of these emission for decades,” he stated. “Among their concerns are health, inability to enjoy their property due to overwhelming smells and metal corrosion observed on surfaces and equipment around their property.

“There is little research which studies residential well-being and the impact on health that chronic exposures to mushroom farming byproducts may have on human health.”

In his study, Cena wrote that exposure to H2S “is dangerous and can create lethal conditions and that exposure to concentrations between 2.0 ppm (parts per million) and 20 ppm can cause fatigue, irritability, poor memory, nausea, dizziness, headaches, respiratory and eye irritation, as well as airway constriction for those with asthma."

Over the past several years, health-related agencies have established various guidelines for H2S levels; for instance, while the Occupational Safety and Health Administration (OSHA) enforces an H2S limit of 20 ppm in occupational settings such as mushroom composting facilities, the Pennsylvania Department of Protection (PA DEP) has set acceptable H2S levels at 0.005 ppm averaged over 24 hours and 0.1 ppm averaged over one hour. 

‘Elevated and irregular’ levels of Hydrogen Sulfide measured

As part of their study, Cena and his team set up three monitors at locations between 100 and 600 feet of suspected sources of emissions and at elevations similar to area compost production facilities – between 350 feet and 435 feet in height. During a reading at one location in December of 2023, the study’s results showed “elevated and irregular” levels of H2S that saw lower limits of detection registered at 0.5 ppm and upper limits of detection that spiked to 100 ppm, well above the PA DEP’s ambient air quality standard of 0.1 ppm averaged over the course of one hour. 

“The device was able to demonstrate that the PA DEP ambient air quality standards had been exceeded,” the report wrote. “However, concentrations at or above 100 ppm were only identified at this sampling location and appear atypical, indicating that the device may have been experiencing a sensor malfunction. H2S concentration [at Location A] did not violate occupational standards, but did exceed ambient air quality standards in Pennsylvania.”

At all three locations, elevated concentrations of H2S were observed primarily from midnight to 8 a.m., when 42 percent of peak readings were observed, while in contrast, 26 percent of peak readings were recorded between 8 a.m. and 4 p.m. The study concluded that composting operations conducted overnight or in the early morning hours cause increases in H2S levels in residential communities.

Report overlaps Sept. 4 New Garden presentation

The written report served as a rehashing of Dr. Cena’s oral presentation on Sept. 4, 2024 at the New Garden Township Building, where before the township board and a capacity audience of residents, he said that the levels of H2S measured during his research were as much as 33 times higher than the recommended levels established by the DEP for the general public. During his concluding remarks, he urged the mushroom industry to identify “point sources and tasks” to lessen potentially harmful H2S levels at composting plants throughout Chester County as part of a collaboration between researchers, local governments, mushroom operators and the American Mushroom Institute (AMI). 

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. 

Following Dr. Cena’s findings, the meeting was opened up to public comment, when nearly two dozen residents shared the side effects of exposure to H2S, not just with their health but the corrosive effects the gas was having on their household appliances.

At the meeting, the AMI introduced a nine-month Mushroom Farm Compost Hydrogen Sulfide Mitigation Pilot study it is conducting in partnership with the Director of the Mushroom Research Center at Penn State that involves the installation of six MultiRae gas monitors and a weather station that captures and calculates H2S levels at a Chester County farm.

In addition, the study is exploring a possible H2S mitigation practice that will involve the application of carbon activated tarps over wastewater “lagoons” to see if they lessen H2S levels. 

Recommendations

In the report’s conclusion, Cena wrote that employees, residents and the general population should be protected from exposure to H2S, as well as methane and ammonia – other common by-products of mushroom composting emissions, stating that “exposure to these gases is known to cause delirious effects to health and pose a nuisance concern at lower concentrations.”

Cena also made the following five recommendations:

• Evaluate the sources of the gas releases and quantify the concentrations from the source within the mushroom composting facilities
• Remedy deficiencies in business operating procedure in comparison to the Best Practices for Environmental Protection in the Mushroom Farm Community, published in 2012 by the PA DEP 
• Inform residents and other stakeholders of chronic exposure to H2S and its consequences to human health
• Consult with a professional engineer and a certified industrial hygienist to evaluate business procedures associated with the release of hazardous gases, and
• Consult with health officials to determine the impact that chronic exposure to odorous gases from mushroom composting facilities such as H2S has on residents’ health and wellbeing.

The township said on its website that it has forwarded the report to all requisite state and county officials and encourages residents to reach out to local legislators and state regulatory agencies with questions or concerns.

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