Smells Like Trouble

Becca Barrus

Becca Barrus

CDE Fire

*To take the corresponding CDE quiz, visit the College of Emergency Dispatch.*

Statistically, Protocol 66: Odor (Strange/Unknown) in the Fire Priority Dispatch System (FPDS®) isn’t a Chief Complaint you’ll be using on a regular basis as an Emergency Fire Dispatcher (EFD). The International Academies of Emergency Dispatch® (IAED) Data Center shows that out of the roughly 1.4 million fire calls in its database from May 2020 to May 2023, only about 9,000 were handled using this Protocol. 

When you do receive a call that should be handled on this Chief Complaint, it will probably be low acuity. However, like every Protocol, you should never assume anything about the situation’s severity until you have all of the information. What you think is a caller complaining about a rotting animal under their porch could actually be a natural gas leak or worse.

According to Mike Thompson, Fire Protocol, Academics and Standards Expert, the caller often won’t give you the full story right out of the gate. “You’ll have to tease it out of them with the Key Questions.”

There aren’t very many Key Questions on this Chief Complaint, but they’ll get you enough information to pass on to the firefighters so they can safely and confidently head to the scene.

The three Determinant Code levels on Protocol 66: Odor (Strange/Unknown) are CHARLIE, BRAVO, and ALPHA. The fact that there aren’t any DELTA-level Determinant Codes doesn’t mean that you can literally phone it in when handling these calls! When you ask the Key Question “What does the odor smell like?” there are options to shunt to six other Chief Complaints that have arguably higher stakes: Protocol 55: Electrical Hazard, Protocol 59: Fuel Spill/Fuel Odor, Protocol 60: Gas Leak/Gas Odor (Natural and LP Gases) if they describe a rotten eggs or sulfur odor, Protocol 61: HAZMAT, Protocol 68: Smoke Investigation (Outside), and Protocol 69: Structure Fire.

“This is like the MPDS® Protocol 26: Sick Person (Specific Diagnosis),” said Gary Galasso, Chair, IAED Council of Fire Standards. “Start here, and if you can, shunt to a more appropriate Chief Complaint that fits better. When in doubt, err on the side of caution.”

If the caller reports a sick person  or sick persons inside or outside in conjunction with an unusual odor, it will be handled with a CHARLIE-level Determinant Code. But remember that “if the foremost chief complaint includes an unconscious person in a vehicle or enclosed space AND an odor of rotten eggs or sulfur, use Protocol 61” (HAZMAT) because it could be a chemical suicide or a similar situation involving dangerous chemicals.

As a side note, although the Additional Information section of this Protocol talks about carbon monoxide, you will likely NOT be handling calls about carbon monoxide poisoning here. Even if people on scene are exhibiting telltale symptoms—such as headache, dizziness, vomiting, chest pain, and/or confusion—it is an odorless gas. Calls of this nature are better handled on Protocol 53: Service Call or with the Medical Priority Dispatch System (MPDS), if your center uses it.

A Rule on Protocol 66 tells you that “unknown odors coming from an appliance should be coded as a 66-A-1” (Odor inside). Why would a weird smell coming from a toaster or dryer be an issue for the fire department? Why not call a maintenance worker instead?

“It’s probably an electrical odor, but if the caller doesn’t describe it as such, don’t shunt to Protocol 55: Electrical Hazard,” Thompson said. “It could be clothes in a washer or dryer that have gotten hot. It could be food in a toaster or microwave. More often than not, the smell happens because something’s wrong with the appliance.”

He described a case where the caller said that they had turned their oven on and reported a funny smell without opening the oven to find out what it was. When the firefighters showed up, it turned out to be a pizza box that had been placed inside and forgotten about. It’s a silly anecdote, but it’s always better to be safe than sorry. Because the fire department came to investigate, the pizza box didn’t catch fire and set the whole building ablaze.

Another unlikely but common source of strange and/or unusual odors is corpses. When a body decomposes, it releases dozens of different chemical compounds, some of which have recognizable odors, including cadaverine and putrescine (smells like rotting flesh), skatole (a strong fecal odor), indole (musty, mothball-like smell), hydrogen sulfide (smells like rotten eggs), methanethiol (smells like rotting cabbage), and dimethyl disulfide and trisulfide (foul, garlic-like odor). Rats or other rodents will sometimes crawl into walls or vents and die there, leaving behind this awful stench. It could also come from dogs or cats, or even a human. Thompson said people will sometimes kill themselves in storage units and won’t be found until a worker or someone who rents a nearby unit complains about the smell.

The Additional Information section also contains odor descriptions that are often associated with illegal laboratories and/or drug operations. If the caller describes the odor as acetone, ammonia, bittersweet, or cat urine or says that it leaves a metallic taste in the mouth, you may want to shunt over to Protocol 61: HAZMAT, which has a suffix and Critical EFD Instructions (CEIs) that are better suited to those situations.

If the caller identifies the smell as belonging to a meth lab or something similar, you will pass it off to the appropriate police dispatchers, whether they are inside or outside your agency. 

Speaking of CEIs, there’s one CEI for Protocol 66: Odor (Strange/Unknown). It has you “determine a specific, clear meeting point for the emergency crews.” In cases where a weird odor is reported in an area that’s considerably large, like a farm or an apartment complex, it saves the firefighters time if someone familiar with the area comes to show them precisely where it is.

“There was a plant in our area we went to fairly frequently for different reasons,” Thompson said. “Whenever we went to the property, we had someone meet us so we knew exactly where the issue was.”

As always, because the FPDS is made to fit the needs of those using it every day, check what Jurisdictionally Approved Instructions your agency has for these types of calls. Will you notify your local EMS group even if there aren’t any sick people involved? Will you notify your public utilities groups if it involves pipes?

“Don’t brush by the CEIs too quickly!” Galasso urged. Take time to learn what you’ll be asking and who you’ll be contacting so you’ll be fully informed and prepared for these types of calls.

When Galasso was in the fire service, they received multiple calls for an odor over a span of months from the same neighborhood. The fire department went out again and again but couldn’t find the source of the odor. Finally, the mystery was solved. It turned out that there was a metal refuse yard upwind a mile away where discarded gas pipes were being moved from one place to another, and the pipes still had mercaptan (a gas odorant that makes odorless gases easier to track) in them. Each time they were moved, it sent the odor downwind throughout the residential neighborhood!

A lot of the time when the fire department gets on scene, the source of the odor is difficult or impossible to find. Still, it’s better to be overprepared than underprepared. Each person’s sense of smell is different. One person might think they smell smoke, while another person thinks it’s something else completely. A report of a weird smell in the basement might actually be a gas leak if the caller doesn’t know what natural gas smells like. It’s better for the fire department to show up with more tools than they end up using than to show up unprepared to a scene that could go up in flames at any moment.