Another celebration of the Fourth of July on Chautauqua Lake highlighted by burning emergency highway flares along its shores has endured this beautiful local custom. Last year, my friend who lives year round on the lake and participates in the flare burning custom, expressed concern about the potential contamination of the lake by the ash from burned flares. We decided to investigate the chemistry of the flare and its combustion products.
You can rest at ease because when the flare is ignited according to printed instructions - when one avoids smoke inhalation - and when one avoids tampering with unburned flare contents, it is personally safe and the environmental impact is minimal. Therefore, continue to enjoy the July Fourth flare lighting and appreciate the flare as a safety device in event of an automobile emergency.
This investigation began with a telephone call to a flare manufacturer, Orion Safety Products/Standard Fusee Corporation in Easton, Maryland. The company sent me four pages of specifications describing flare ingredients, storage procedures, personal protection limits, toxicology and regulatory information. Since the flare burns slowly for 30 minutes, stores safely in an automobile trunk and is inexpensive attests to the thoughtful chemical engineering involved in designing this long-used product.
The author observes a burning 30-minute highway flare in his driveway several days before the flare lighting around Chautauqua Lake on the Fourth of July.
Although very technical, a list of the nine flare ingredients, describing their function during the burn will follow because I think it is fascinating and educational, although perhaps, minutiae.
1. The flare is labeled, "Contains Perchlorate" as a warning since unburned Perchlorate interferes with iodine uptake by the thyroid gland. Perchlorate releases oxygen to support combustion even when the flare is wet.
2. Strontium nitrate releases oxygen during combustion.
3. Sulfur burns at low temperature and is a primary ingredient of gunpowder.
4. Paraffinic oil is a petroleum product easily ignited.
5. Potassium chlorate releases oxygen and is also used as a wound antiseptic.
6. Sawdust in its purest form is cotton which burns intensely.
7. Marble dust helps compact and hold the flare contents together. The dust contains calcium carbonate used in baby diapers and industrial sand called "quartz silica."
8. Shellac holds the chemicals together and is produced by Asian insects.
9. Burnt umber contributes the red color and contains manganese which in high doses is toxic.
The state of California established a list of chemicals that cause cancer, developmental and birth defects called, "Proposition 65." Flare ingredients of saw dust, marble dust, potassium chlorate and burnt umber are on this list.
The hazardous decomposition products from the flares are identical to the massive quantities of similar gases produced from burning coal, natural gas and automobile gasoline. They are:
1. Carbon monoxide which interferes with hemoglobin uptake of oxygen in the blood.
2. Carbon dioxide which is the gas animals exhale and contribute to global warming.
3. Nitrogen oxides which participate in vital human physiology and one, laughing gas, is used as an anesthetic. Over exposure can cause lung swelling.
4. Sulfur oxides which are used to preserve wine and fruit but overexposure causes irritation of the eyes, throat and choking.
I personally inhaled smoke of a burning flare and found it noxious. Finally, the significance of the burned ash, which initiated this investigation, still remains a secret. Company representatives told me on two occasions, "the slag or ash is a mixture of sodium salts which just wash away in the rain."
Curiously, the listed ingredients include potassium but sodium is absent. The ash deposited on my driveway after burning one flare did indeed wash away in a recent rain. During my search I learned government regulators consider small quantities of ash safe, described as "trivial activity," when washed into streams, lakes and public water supplies. Remember, partially burned flares as opposed to completely burned flares contain toxic ingredients so require special disposal. I recommend disposing of the cooled burned flare ash and wire supports in the trash to keep them out of the lake.
Next time you light up a flare, stand clear, appreciate its chemical complexity, beauty and safety protection it can provide on the highway.