Welcome to Quandary This! Chemistry in the News, a monthly series promoting the integration of peer-reviewed literature in science education through current events and real-world questions. This month, we explore research on the chemical suppressants used to control recent urban wildfires.

An aerial photograph of a burned neighborhood from Marshall wildfire, Louisville, Colorado 2021.

Australia in 2020. Canada in 2023. Texas in 2024, and California in 2025. Fires make headlines. They’re attention grabbers, they’re destruction for everything in their path, and they’re hard to get away from these days. But what most people don’t think about—actively try not to think about—is the aftermath.

Many factors can affect the cleanup and usability of land after the fire has been put out. The chemical mechanisms used for fire suppression can affect safety, and toxic chemicals that are regularly stored in homes, all need to be accounted for when considering the personal safety of cleanup workers as well as the environment.

Fire retardant is often dropped from airplanes to coat the area where fire is expected to spread next. The pink color of the retardant used recently in California has caused some people to question what is in the retardant and if it’s safe.

For answers to these questions and more, we encourage students to turn to peer-reviewed literature from trusted publications like ACS.

Jump to Section
Challenge 1: Literature Research
Challenge 2: Essay Investigation
Challenge 3: In-Depth Analysis
Suggested Reading

Challenge 1: Literature Research

For Teaching Professionals: The following questions are intended to help students learn the critical skill of searching trusted sources of information, such as peer-reviewed literature, to find answers to specific questions. We encourage instructors to assign these questions to students enrolled in any introductory chemistry lab or lecture. By using literature to find the answers, students will learn to search and consume trusted scientific content with the intent uncovering specific information. The grading is up to you, but we strongly recommend holding students accountable to presenting a clear answer to each question and accurately tie that answer to a properly cited source.

Prompt: For each of the following questions, provide an answer and cite the source of your information in ACS style. You can view citation examples and guidance in the ACS Style Quick Guide.

All the questions posed below can be answered in the journals, books, and news published by ACS. While it is not the only reputable source of peer-reviewed information, the Suggested Reading list below may help you answer most, if not all, of these questions. Make sure you are logged in to your institution's library portal if you wish to search for additional sources on the ACS Publications website.

  1. What is the chemical structure of the primary ingredient in the firefighting retardant frequently being used in fires, most recently in the California wildfires? What additive chemicals are included and why?
  2. What is the name of the primary chemical reaction taking place? How does this chemical modification cause a compound to char instead of burn?
  3. Do chemical fire suppressants work better than just coating an area with water? Why or why not?
  4. What toxicity concerns exist? To humans? To wildlife?
  5. What historical flame retardants have been largely put out of service? Why?

Challenge 2: Essay Investigation

For Teaching Professionals: The following essay question is intended to help students go one step beyond simple question and answer research. This exercise encourages students to not only consider a multi-disciplinary exploration around a topic, but to also develop written communication skills. As with other questions in this series, the grading is up to you, but we encourage you to help students develop a clear and concise style. Where possible, utilize chemical drawing utilities or neat handwritten molecules and mechanisms. The ideal answer should take no more than one sheet of paper. The ACS Guide to Scholarly Communication can be a great reference.

Prompt: What is the chemical fate and environmental/health impact of reactive pollutants from wildfires such as sulfur, nitrate radials, ash, and more? Identify one or more pervasive pollutants. Provide an exploration of the structure, the mechanism of creation, and the mechanical or biological mechanisms of the structures it attacks.

The Suggested Reading list is designed to provide a solid foundation to help answer this question, but we encourage you to search and explore beyond these suggestions. If you encounter content that is not free to read, please ensure you are logged into your institution’s library portal. If you still are unable to access the content you need, please recommend the content to your library or contact them directly to let them know there are articles you’d like to read.

Challenge 3: In-Depth Analysis

For Teaching Professionals: The following question will challenge students to uncover understanding around the business and legal implications of technological advance. This challenge may be helpful for anyone who wants to build depth of thinking and understanding around the real-world circumstances involved in the application of technology. This may include business students, journalism students, and students interested in studying business or intellectual property law.

Prompt: The patent for Phos-chek cites many research articles, including an ACS article by Fiss et al. Given that patents are designed to secure ownership of novel discoveries and patent citations typically paint the landscape of “prior art” to demonstrate that their discovery is novel, what claim does the patent make that could be considered an advance upon the discoveries outlined in this article?

Suggested Reading

An Effective Way To Flame-Retard Biocomposite with Ethanolamine Modified Ammonium Polyphosphate and Its Flame Retardant Mechanisms

Mechanochemical Phosphorylation of Polymers and Synthesis of Flame-Retardant Cellulose Nanocrystals

Aluminum Hypophosphite versus Alkyl-Substituted Phosphinate in Polyamide 6: Flame Retardance, Thermal Degradation, and Pyrolysis Behavior

Seasonal Impact of Phosphate-Based Fire Retardants on Soil Chemistry Following the Prophylactic Treatment of Vegetation

Metals in Wildfire Suppressants

Physical Health Symptoms and Perceptions of Air Quality among Residents of Smoke-Damaged Homes from a Wildland Urban Interface Fire

Forest fires kindle demand for fire-fighting chemicals

Government Watch: California first in U.S. to prohibit flame retardants

For fun: Periodic Graphics: Suppressing wildfires with chemistry

Be the First to Receive New Quandaries!

Quandary This! Chemistry in the News is a monthly series designed to help chemistry educators and their students explore the fascinating world of chemistry as it relates to real-world events and current news stories.

There are a few ways to find out when the newest quandary is available. The easiest way is to sign up for our monthly Education Insider newsletter and get alerted for new releases in this series. We will also update our series posts with the latest episodes, or you can use the ACS Axial search feature above for the latest Quandary This! updates.

Want the latest stories delivered to your inbox each month?