Statement by
LT Michelle Colledge
Environmental Health Scientist
Division of Regional Operations
Agency for Toxic Substances and Disease Registry
U.S. Department of Health and Human Services
ATSDR’s Public Health Activities in Warren Township, Ohio
The Economic Development and Environment Committee Ohio State Senate

May 11, 2005

Mr. Chairman and Members of the Committee, thank you for inviting me to testify before your committee. My name is Michelle Colledge, and I am an Environmental Health Scientist in the Division of Regional Operations, at the Agency for Toxic Substances and Disease Registry (ATSDR). ATSDR is a federal agency within the United States Department of Health and Human Services. The mission of ATSDR is to “serve the public by using the best science, taking responsive public health actions, and providing trusted health information to prevent harmful exposures and disease related to toxic substances.”

ATSDR testimony is not intended to address the specific provisions or merits of any proposed legislation. Today, I will provide the committee with information about Construction and Demolition debris landfills, an overview of the toxicity of hydrogen sulfide gas, and a summary of ATSDR’s public health activities in Warren Township, Ohio. I will include an overview of ATSDR’s investigation concerning the Warren Recycling facility, any conclusions drawn and recommendations stemming from our involvement there, and potential health effects from exposures to hydrogen sulfide.

Construction and Demolition (C&D) Debris Landfills
Debris from construction and demolition (referred to as C&D waste) is a substantial waste stream in the United States, with hundreds of millions of tons of C&D waste being generated each year(1). The United States Environmental Protection Agency (USEPA) defines C&D debris as waste material that is produced in the process of construction, renovation, or demolition of structures. It consists of concrete, asphalt, wood, metals, gypsum wallboard, and roofing.

Of the components of C&D waste materials, drywall is of special concern. It is a major component of C&D wastes, and its disposal in C&D landfills can result in the production of hydrogen sulfide. Drywall is composed of a core of gypsum (CaSO4•2H2O), covered on both sides with a paper facing and backing(2). When the sulfate in the gypsum is exposed to water, it becomes solubilized in the landfill leachate, and hydrogen sulfide gas is produced through an anaerobic conversion process(3).

Effects of Hydrogen Sulfide Exposure
Hydrogen sulfide is a colorless, flammable gas under normal conditions. In air, people can smell hydrogen sulfide at levels as low as 0.5 parts per billion (ppb), and the odor is usually characterized as smelling like “rotten eggs” or “sewage.” Because hydrogen sulfide is ubiquitous in the natural environment, low-level exposures are not uncommon. Natural sources account for approximately 90% of the amount of hydrogen sulfide in the atmosphere. Background concentrations of hydrogen sulfide in outdoor air are typically less that 1 ppb(4).

Short-term exposures to high levels of hydrogen sulfide may cause adverse health effects, including: airway constriction in individuals who have asthma5; decreased lung function6; inability to smell gas (olfactory fatigue)(7-8); and eye irritation (keratoconjunctivitis, punctate corneal erosion, blepharospasm, lacrimation, and photophobia)(9-15). Severe injury and death have been observed with short-term exposures to hydrogen sulfide levels exceeding 100 ppm4, (16-17). Acute exposures to elevated levels of hydrogen sulfide can result in pulmonary edema and central nervous system effects including dizziness, nausea, headache, and physical collapse(18-21).

Long-term exposures to hydrogen sulfide may also result in adverse health effects. These include: neurologic effects (fatigue, loss of appetite, nausea, headache, vomiting, irritability, poor memory, depression, motor skills, and dizziness)(9, 22-23) and respiratory effects (nosebleeds, breathing abnormalities)(23-25). Several studies have been conducted which show neurologic effects from chronic low-level exposures. These studies have documented deficits in cognitive function, reduced perceptual motor speed, impaired memory, impaired balance, and abnormal mood status. These effects were still evident months and sometimes years after exposures ceased (22-23, 26). The magnitude of exposure in these studies ranged in low parts per billion to low parts per million. As an attachment to my written testimony, I have included a table that outlines current health-based guidance values for hydrogen sulfide exposures.

Summary of ATSDR Investigation in Warren Township
The Warren Township Administration and LaBrae School District petitioned ATSDR in May 2002 to investigate whether illnesses being reported in their community could result from exposures to hydrogen sulfide emissions from the Warren Recycling, Inc. (WRI) C&D landfill. Some residents of the Warren Township Community report that they have experienced symptoms they believe are related to chronic hydrogen sulfide exposure, beginning in fall of 200124. Of special concern to ATSDR is the fact that approximately 1600 students attend a high school and two elementary schools near the landfill (two of which are less than ½ mile from the landfill).

ATSDR began its investigation in the Warren Township Community in August 2002, when we held a public availability session to gather health concerns. More than 150 residents reported similar health effects that they and their families were experiencing, including nausea, headache, vomiting, eye irritation, fatigue, dizziness, and memory loss. Preliminary, unvalidated air samples collected by the landfill’s contractor detected a peak concentration of 13 parts per million (ppm) hydrogen sulfide in residential outdoor air. Exposures to this concentration of hydrogen sulfide have been associated with the kind of health effects reported in the Warren Township community. However, insufficient data were available to adequately characterize the levels of exposures within the community. To more fully evaluate exposures, ATSDR conducted an Exposure Investigation, sampling indoor and outdoor air in seven community locations for five months. Air sampling during the Exposure Investigation detected a maximum concentration of 6.1 ppm in residential outdoor air, a level that has been demonstrated to cause headaches and airways restrictions in experimental studies of people with asthma. Some levels were above those associated with increased asthma-related hospital visits for children and reports of eye irritation in occupational and animal studies. Using the detected concentrations of hydrogen sulfide in residential areas and uncontrolled releases from landfill conditions, ATSDR concluded that these conditions posed an urgent public health hazard to citizens of Warren Township. ATSDR uses the “urgent public health hazard” conclusion for sites at which short-term exposures (less than 1 year) to hazardous substances or conditions could result in harmful health effects that require rapid intervention. ATSDR released a report on the Exposure Investigation on November 21, 2003. I have entered a copy of the report into the record. ATSDR recommended the following actions:

1) Warren Recycling Incorporated should stop community member airborne exposure to hydrogen sulfide from outdoor sources as soon as possible. (Status: Pending enforcement action)

2) ATSDR should conduct air sampling for other sulfur gases during “odor events,” timies when residents report smelling unusual or strong odors.
(Status: Completed)

3) ATSDR and the Ohio Department of Health should conduct a health study of the population.
(Status: Completed 2004; final report pending)

4) The Ohio Environmental Protection Agency, the City of Warren and Trumbull County Health Departments should identify the source(s) of hydrogen sulfide. (Status: Completed)

5) ATSDR should contact the National Institute for Occupational Safety and Health (NIOSH) to determine if there is a need for a health hazard evaluation of landfill workers. (Status: NIOSH contacted; the landfill owner/operator has not granted access.)

6) Warren Recycling Incorporated should reduce the threat of fire and explosion that exists on the landfill and/or from landfill operations.
(Status: Not adopted. Fires are still occurring.)

7) Warren Recycling, Inc. should restrict community access to the landfill.
(Status: Not adopted)

As a follow-up to the initial Exposure Investigation, ATSDR conducted additional testing for other sulfur gases. C&D landfills are known to release mercaptan, carbon disulfide, and other organic and inorganic sulfur compounds3. The Exposure Investigation identified elevated levels of methyl mercaptan, dimethyl sulfide, and n-butyl mercaptan in additional to hydrogen sulfide.

Continued community concern and continued odor complaints prompted the Ohio Department of Health’s State Epidemiologist to request that ATSDR help conduct a health investigation in late May 2004. ATSDR conducted the field portion of this investigation in June and July of 2004. Participants in this study consisted of 107 community members who live, work, or attend school within a 1-mile radius of the facility. From results of a pre-screening respiratory questionnaire, participants were placed in one of three categories: 1) those with existing respiratory conditions, such as asthma (50 people), wore personal air-monitoring badges, kept a daily diary of odors and symptoms, and tested their lung function twice a day using a peak-flow meter instrument, 2) those without existing respiratory conditions (50 people) wore the personal air monitoring badge and kept the daily diary or 3) those who only kept a daily diary (7 people). Residents of five homes also allowed ATSDR to place hydrogen sulfide outdoor air monitors in their yards for the study period. ATSDR anticipates presenting our findings to the community in late spring or early summer of this year.

During the field data collection phase of this study, ATSDR used a real-time hydrogen sulfide monitor to respond to community odor complaints. During one such response, ATSDR found levels of hydrogen sulfide up to 95 ppm in residential air. This prompted a letter from ATSDR’s Assistant Administrator to the Warren City Health Director(27). The letter stressed the urgent nature of these elevated hydrogen sulfide readings and recommended the city 1) develop the capacity to monitor for hydrogen sulfide in response to future odor complaints; and 2) develop contingency plans with city, township, and Trumbull County emergency response personnel to shelter-in-place or evacuate community members, based on hydrogen sulfide readings. The City Health Department committed to working with the City Wastewater Treatment Plant to share hydrogen sulfide monitoring devices, and agreed to pursue contingency planning.

Throughout our involvement with this site, ATSDR has worked with partners at the local, state, and federal level. Because explosive levels of landfill gases have been measured on-site(28), and several underground fires have been detected and addressed on-site, ATSDR worked with the LaBrae School Board, local fire stations, and the Trumbull County HAZMAT manager to create a response and evacuation plan in the case of a substantial odor event. ATSDR has provided health advice and guidance to the Warren City Health Department, the Ohio EPA, and the USEPA

ATSDR has determined that residential exposures to hydrogen sulfide pose a health hazard to residents in the Warren Township community. The siting of the landfill within an existing community, in combination with construction and maintenance inadequacies of the landfill, has allowed these conditions to become a substantial problem for the health and safety of nearby residents and for the state of Ohio. These concerns have led Ohio EPA to request an Emergency Removal Action under the USEPA’s Comprehensive Environmental Response, Compensation, and Liability Act authority, which was accepted and is currently in progress. ATSDR has worked very closely with local, state, and federal health and environmental agencies at this site. Since ATSDR became involved at the Warren Recycling Landfill, similar odor problems have been identified at other C&D landfills in Ohio.

Thank you for inviting me here to testify before the committee. I have provided you with information related to C&D debris in landfills, the toxicity of hydrogen sulfide gas, and ATSDR activities in Warren Township, Ohio.

Attachment 1

Guidance values for inhalation exposure to hydrogen sulfide

Concentration, ppb

Exposure Period






14-365 days

Intermediate MRL


1 hour



14 days






10 minutes

NIOSH 10 minute ceiling


1 hour


USEPA: U.S. Environmental Protection Agency

RfC: Reference Concentration–level protective of public health, even sensitive populations

MRL: Minimal Risk Level–level protective of public health, even sensitive populations

AIHA: American Industrial Hygiene Association

ERPG: Emergency Response Planning Guide–1-hour level of exposure that would result in mild, transient health effects (ERPG-1), irreversible health effects (ERPG-2), or serious injury or death (ERPG-3).

NIOSH: National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention

Attachment 2

References for Michelle Colledge Testimony before the Economic Development and Environment Committee of the Ohio State Legislature

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  14. Lopez, A., Prior, M., Yong, S., LiLie, L., & Lefebvre, M. (1988a). Nasal Lesions in Rats Exposed to Hydrogen Sulfide for Four Hours. American Journal of Veterinary Research, 49, 1107–1111.

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  17. Integrated Risk Information System, (2003). Hydrogen Sulfide. United States Environmental Protection Agency. Accessed April 2005: http://www.epa.gov/iris/.

  18. Milby, T.H. & Baselt, R.C. (1999). Health Hazards of Hydrogen Sulfide: Current Status and Future Directions. Environmental Epidemiology and Toxicology, 1, 262-269.

  19. Parra, O., Monso, E., & Gallego, M. (1991). Inhalation of Hydrogen Sulphide: A Case of Subacute Manifestations and Long Term Sequelae. British Journal of Industrial Medicine, 48, 286-287.

  20. Snyder, J.W., Safir, E.F., & Summerville, G.P. (1995). Occupational Fatality and Persistent Neurological Sequelae After Mass Exposure to Hydrogen Sulfide. American Journal of Emergency Medicine, 12, 199-203.

  21. Tvedt, B., Edland, A., & Skyberg, K. (1991). Delayed Neuropsychiatric Sequelae After Acute Hydrogen Sulfide Poisoning: Affection of Motor Function, Memory, Vision, and Hearing. Acta Neurologica Scandinavica, 84, 348-351.

  22. Kilburn, K.H. (1997). Exposure to Reduced Sulfur Gases Impairs Neurobehavioral function. Southern Medical Journal, 90(10), 997-1006.

  23. Kilburn, K.H., & Warshaw, R.H. (1995). Hydrogen Sulfide and Reduced-Sulfur Gases Adversely Affect Neurophysiological Functions. Toxicology and Industrial Health, 11(2), 185-197.

  24. Agency for Toxic Substances and Disease Registry. (2002a). Public Health Consultation: Hydrogen sulfide exposure in Warren Township; Trumbull County, Ohio. Atlanta, GA: U.S. Department of Health and Human Services.

  25. Campagna, D., Kathman, S., Pierson, R., Inserra, S., Phifer, B., Middleton, D., Zarus, G., & White, M. (2004). Ambient hydrogen sulfide, total reduced sulfur, and hospital visits for respiratory diseases in Northeast Nebraska, 1998-2000. Journal of Exposure Analysis and Environmental Epidemiology, 14, 180-187.

  26. Kilburn, K.H. (1999). Evaluating Health Effects from Exposure to Hydrogen Sulfide: Central Nervous System Dysfunction. Environmental Epidemiology and Toxicology, 1, 207-216.

  27. Agency for Toxic Substances and Disease Registry (2004b). Letter from ATSDR Administrator to Warren City Health Commissioner. Atlanta, GA: U.S. Department of Health and Human Services.

  28. Paul C. Rizzo Associates, Inc. (2002). Field Activity Daily Logs. Monroeville, PA:

  29. Last Revised: May 12, 2005