Q: What was CTEH’s role in the East Palestine, Ohio rail incident?
A: CTEH was hired by Norfolk Southern to conduct airborne chemical screening in residents’ homes, surface water sampling, and worker and community outdoor air monitoring and sampling in East Palestine and the surrounding areas.
Q: Why were some chemicals related to the derailment and fire not monitored for during the derailment and subsequent vent and burn of the vinyl chloride car? Why were action levels changed during monitoring for home assessments?
A: When CTEH is mobilized for an incident, much of the first hours of the response is focused on communication with the responsible party or first responders in an effort to identify as many of the potential chemical and physical hazards as possible. In a derailment, monitoring and sampling priority is given to chemicals confirmed or suspected to be released, which is then prioritized according to risk to human health. Once arriving on site and confirming actual breached or leaking vessels, the sampling strategy dials in to a more specific chemical set. Initial evaluation also includes assessing chemicals that are produced through combustion, incomplete combustion, reactions with water or humidity, reactions with oxygen or metals, reactions with other chemicals, and even the weathering effects of solar radiation. Real-time monitoring technology with the level of specificity required to assess for individual chemicals is limited.
For many suites of chemicals, colorimetric tubes, tapes, and wipes are used, which may have lower sensitivity than electronic electrochemical monitoring solutions. Many of the chemicals of interest may be detected on real-time devices that are less specific but highly sensitive – they simply require the application of a correction factor to the value which is then compared to an action level. On multichemical responses, CTEH often uses these technologies together: a detection on a less specific instrument requires a validation with a secondary instrument that is more specific to confirm which chemical is present in order to identify subsequent follow-up actions.
CTEH relies on the experience of our technical subject matter experts, PhD toxicologists, in conjunction with reviewing published research data and advising from chemical manufacturers, state and federal agencies, and other response contractors. In complex multichemical situations and especially when fire is present, risk management decisions have to be made by the Unified Command based on combined data and experiences. Incomplete combustion of vinyl chloride yields negligible percentages of other hazardous chemicals such as phosgene, which was classified as being low risk given that it was extremely unlikely that anyone in the work area or community would be exposed to a concentration or a duration that would yield any negative health effects.
Information and strategies are often fluid on a response. As new hazards emerge or are eliminated, the sampling and monitoring strategy adjusts to either incorporate or remove those items from the operational plan, which is continuously evaluated based on new data. For this incident in particular, the Agency for Toxic Substances and Disease Registry (ATSDR) was consulted in addition to EPA for screening value consultation for butyl acrylate. Incident Command agreed on an initial level that was conservative, 3,300 ppb – approximately 1/3 of the EPA Acute Exposure Guideline Level-1 (AEGL-1). The AEGL-1 is a guideline at which the airborne concentration of a substance may cause transient, reversible, and non-disabling discomfort, irritation, or other nonsensory effects in the general population. Not long after, ATSDR suggested lowering the screening level by a factor of 10 to 330 ppb to account for individuals living in their homes 24 hours per day, which was adopted and incorporated into the Unified Command plan, with input from local and regional health departments, health and environmental agencies from Ohio and Pennsylvania, EPA, and Norfolk Southern. Weeks later, once most home screenings were complete, ATSDR further adjusted their recommended screening value to 20 ppb, more than an order of magnitude lower than the original recommendation. The new value was intended to minimize odors and has no relation to any suspected or unknown health effects.
Q: What chemicals did CTEH test for when conducting indoor air screening? Was vinyl chloride (VC) detected in homes?
A: CTEH conducted indoor air screening per the EPA approved air screening plan for VOCs and vinyl chloride (VC), the primary health risk driver of the compounds released in the derailment, in the homes of residents who requested screening. VOCs, which can be commonly detected in household from a variety of different causes, including aerosol sprays, candles, and disinfectants, were detected in some homes; however, VC was not. Results were provided to the residents, and the data from homes collectively did not indicate short- or long-term risks to human health.
As of February 2024, CTEH has not been contracted to conduct any additional indoor air monitoring.
More information about VOCs can be found here: USEPA Indoor Air Quality Information
Q: Why didn’t CTEH test for dioxins?
A: There was no scientific basis for sampling for dioxins in people’s homes following the train derailment and burn. Dioxins are ubiquitous in the environment, can be created by many combustion sources, and were not expected to be significant combustion products of the prescribed burn conducted on the VC cars involved in the derailment. CTEH and the EPA conducted air monitoring for phosgene and hydrochloric acid, two marker combustion products of VC during the prescribed burn and found only a few detections of low concentrations of hydrochloric acid in the community outside the immediate burn area, and only within the initial 24 hours following the burn. For these reasons, dioxin testing was unwarranted and unlikely to provide results relevant to the derailment.
Q: How many homes did CTEH perform indoor air screening for? How many were found to have high or potentially unhealthy levels of vinyl chloride?
A: Over 630 homes and commercial spaces participated in voluntary indoor air screening. Vinyl chloride was not detected in any of the indoor air screenings.
Q: Is CTEH continuing to perform indoor air screening for Norfolk Southern? If not, when did that end?
A: CTEH’s indoor air screening work concluded in April 2023. More information regarding the conclusion of indoor air screening can be found here: USEPA East Palestine Operational Updates (April 2023) and USEPA East Palestine Newsletter (May 2023)
Q: As of February 2024, what is CTEH’s current involvement with the Norfolk Southern East Palestine train derailment?
A: CTEH continues to work at the direction of Unified Command to support Norfolk Southern in the recovery efforts in East Palestine. Specifically, CTEH experts continue to provide air monitoring in work areas, industrial hygiene consulting, and surface water sampling.