On February 3, 2023, a train derailed in the town of East Palestine, Ohio.1-2 Five of the train cars were carrying vinyl chloride (Figure 1), a compound that is mostly used to make PVC.
Figure 1: Chemical structure of vinyl chloride, C2H3Cl
The vinyl chloride was combusted because of the accident, and also from controlled burning of vinyl chloride initiated by authorities.1,2
Vinyl chloride is a carcinogen, and its combustion of vinyl chloride is known to release HCl, phosgene (COCl2), and CO through a variety of pathways.3 For example, HCl can be formed through the reaction:
2 C2H3Cl(g) + 5 O2(g) → 4 CO2(g) + 2 H2O(g) + 2 HCl(g) Equation 1
Phosgene might be produced through the following reaction:
2 C2H3Cl(g) + 5 O2(g) → COCl2(g) + 3 CO2(g) + 3 H2O(g) Equation 2
In addition, the combustion of vinyl chloride can release dioxins, which are particularly problematic.5
The release of these various substances likely caused various ailments reported by people close to the crash, including headaches, eye irritation, and skin rashes.1,2 Fortunately, no one was killed, but people have reported that chickens, fish, and even a dog died.
I discussed these issues with students in my chemistry classes, introducing them to the chemical equations that could describe the formation of HCl and COCl2 from vinyl chloride combustion (Equations 1 and 2). I also used diffusion of HCl(g) from concentrated HCl(aq) to illustrate how gas phase HCl could have potentially impacted people and animals close to the crash site. All these experiments were conducted in the HOOD (Video 1).
Video 1: Train Derailment Chemistry, Tommy Technetium YouTube Channel (accessed Feb. 28, 2023)
Have you discussed some of the chemistry involved in the recent train accident in Ohio? If so, what kinds of topics did you and your students explore? I’d love to hear any thoughts you might have on how to incorporate this issue into your chemistry classes.
References:
- https://cen.acs.org/safety/Safety-questions-remain-Ohio-train/101/i6
- https://cen.acs.org/safety/Ohio-train-derailment-raises-questions/101/web/2023/02
- O’Mara, M. M.; Crider, L. B.; Daniel, R. L. Combustion Products from Vinyl Chloride Monomer. Amer. Ind. Hyg. Assoc. J. 1971, 32, 153-156.
- Lutrell, W. E.; Sheaman, L. G. Vinyl chloride. Journal of Chemical Health & Safety, 2012, 19, 30-31.
- https://news.cornell.edu/media-relations/tip-sheets/vinyl-chloride-highly-mobile-soils-and-water-east-palestine-area-farmers
Preview image: Drone footage shows the freight train derailment in East Palestine, Ohio, U.S., February 6, 2023 in this screengrab obtained from a handout video released by the NTSB. NTSBGov/Handout via REUTERS
Safety
Safety: Video Demonstration
Safety: Video Demonstration
Demonstration videos presented here are not meant as tools to teach chemical demonstration techniques. They are meant as a tool for classroom use. The demonstrations may present safety hazards or show phenomena that are difficult for an entire class to observe in a live demonstration.
Those performing the demonstrations shown in this video have been trained and adhere to best safety practices.
Anyone thinking about performing a chemistry demonstration should first read and then adhere to the ACS Safety Guidelines for Chemical Demonstrations (2016) These guidelines are also available at ChemEd X.
General Safety
General Safety
For Laboratory Work: Please refer to the ACS Guidelines for Chemical Laboratory Safety in Secondary Schools (2016).
For Demonstrations: Please refer to the ACS Division of Chemical Education Safety Guidelines for Chemical Demonstrations.
Other Safety resources
RAMP: Recognize hazards; Assess the risks of hazards; Minimize the risks of hazards; Prepare for emergencies
NGSS
Students who demonstrate understanding can construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.
*More information about all DCI for HS-PS1 can be found at https://www.nextgenscience.org/dci-arrangement/hs-ps1-matter-and-its-interactions and further resources at https://www.nextgenscience.org.
Students who demonstrate understanding can construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.
Assessment is limited to chemical reactions involving main group elements and combustion reactions.
Examples of chemical reactions could include the reaction of sodium and chlorine, of carbon and oxygen, or of carbon and hydrogen.
Engineering Design - Design a solution to a complex real-world problem is a performance expectation related to Engineering Design HS-ETS1.
Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering.
Using scientific knowledge to generate the design solution: Students restate the original complex problem into a finite set of two or more sub-problems (in writing or as a diagram or flow chart). For at least one of the sub-problems, students propose two or more solutions that are based on student-generated data and/or scientific information from other sources. Students describe* how solutions to the sub-problems are interconnected to solve all or part of the larger problem.
Describing criteria and constraints, including quantification when appropriate: Students describe criteria and constraints for the selected sub-problem. Students describe the rationale for the sequence of how sub-problems are to be solved, and which criteria should be given highest priority if tradeoffs must be made.
Evaluate a Solution to a Real World Problem is a performance expectation related to Engineering Design HS-ETS1.
Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics as well as possible social, cultural, and environmental impacts.
Evaluating potential solutions-In their evaluation of a complex real-world problem, students: Generate a list of three or more realistic criteria and two or more constraints, including such relevant factors as cost, safety, reliability, and aesthetics that specifies an acceptable solution to a complex real-world problem; Assign priorities for each criterion and constraint that allows for a logical and systematic evaluation of alternative solution proposals; Analyze (quantitatively where appropriate) and describe* the strengths and weaknesses of the solution with respect to each criterion and constraint, as well as social and cultural acceptability and environmental impacts; Describe possible barriers to implementing each solution, such as cultural, economic, or other sources of resistance to potential solutions; and Provide an evidence-based decision of which solution is optimum, based on prioritized criteria, analysis of the strengths and weaknesses (costs and benefits) of each solution, and barriers to be overcome.
Refining and/or optimizing the design solution: In their evaluation, students describe which parts of the complex real-world problem may remain even if the proposed solution is implemented.