Video: Introduction to Wildland Fuel Management

American Elk prescribed fire Wind Cave National Park
A firefighter ignites the American Elk prescribed fire in Wind Cave National Park, October 20, 2010. Photo by Bill Gabbert.

When land managers talk about “fuel management”, not everyone knows what they mean. This video can help clarify the term.

It was produced by Northern Arizona University, Wildland Fire Education and Training Collaborative, Joint Fire Science Program, and Southwest Fire Science Consortium.

28 fuel geyser incidents reported in 2018

Fuel and vapor can be expelled with force from a chainsaw fuel tank

fuel geyser incidents map
This map was originally prepared by ExxonMobile to indicate the areas with “U.S. Gasoline Requirements”, hence the shaded areas and the legend at bottom-left. Someone added the Xs for the location, by year, of fuel geyser incidents reported from 2015 to 2018, and the legend at top-right. Click to enlarge.

In 2018 there were 28 reports of fuel geyser incidents, in which fuel and vapor are expelled with force from a fuel tank or container. These can be dangerous, especially when ignition sources may be in close proximity, such as when a person is fighting a fire.

For years the land management agencies have been warning firefighters about the dangers of gasoline being forcefully released from chainsaws. Some of these incidents have occurred with saws that have the newer quarter-turn gas caps. After a saw has been running for a while pressure can build up in the gas tank causing vapor lock, which can prevent the saw from running. Thinking it may be out of fuel, the operator opens the quarter-turn gas cap and the pressure in the tank forces out fuel and vapor. If there is an ignition source nearby, it can quickly ignite and cause very serious injuries.

The Wildland Fire Lessons Learned Center reported that of the 28 fuel geyser incidents reported in 2018, 23 involved chainsaws (21 with Stihl saws and 2 with Husqvarnas). Four incidents occurred with fuel containers, and one occurred with a leaf blower.

Over the last half decade or so several firefighters have been seriously burned in fuel geyser incidents. We reported some of them here, here, and here.

A 2015 report by the Bureau of Land Management identified possible pressurization hazards associated with fuel systems on 12 models of chainsaws:

  • Stihl 036, 044, 046, MS-361, MS-362, MS-441, MS-461, MS-660, MS-880;
  • Husqvarna 340, 345, 350

The BLM and other agencies have been working to figure out why fuel geysers occur and how to prevent additional injuries. On the list of recommendations that they have developed one of the most important is to open fuel caps very slowly and cover the cap with a rag to contain potential fuel geyser spray. If it begins to geyser, close it and let the engine and tank cool for an extended period of time. And don’t open the cap at all if the tank is over half full.

Here is the complete list from the National Wildfire Coordinating Group:

  • Always assume fuel tanks and fuel containers are pressurized.
  • Ensure the cap is correctly secured.
  • Always check fuel levels before opening the fuel tank or filler cap. Fuel levels greater than ½ tank may geyser.
  • Open cap slowly and if able, direct potential spray away.
  • Cover the cap with a rag to contain potential fuel geyser spray.
  • Always check fuel levels before opening a fuel cap.
  • Be extra vigilant when equipment is running poorly with fuel levels above ½ tank.
  • Move at least 20 feet away from any heat source.
  • Start the saw at least 10 feet from the fueling area.
  • Do not use fuel older than one month.

If the equipment is running poorly or vapor lock is suspected:

  • Do not open fuel cap. Relieving the pressure does not alleviate a “vapor lock” equipment.
  • Check fuel level through the tank or use the bar oil level to gage fuel level.
  • If fuel level is over ½ full, DO NOT open the tank.
  • Allow the equipment to thoroughly cool. This could take over 45 minutes.
  • When the equipment is cool, restart the equipment.

This video demonstrates what fuel geysering looks like. I don’t know which is worse — having it happen when you are 30-feet above the ground or near a wildfire.

The National Technology and Development Program’s National Fuel Geyser Project has proposed some possible solutions to fuel geysering, including  1) Vaporless Refueling Systems; 2) Formalized Fuel Geyser Training; 3) Standard Saw/Requirements; 4) No Gas Chainsaws; 5) Specialized Fuel; and 6) Fuel Conditioning.

In the meantime the Project hopes to continue its field evaluation of vaporless refueling systems. This would include 50 test crews and 30,000 refueling cycles from May through November of this year. This field evaluation would be implemented on all handheld-engine powered devices — chainsaws, string trimmers and blowers.

They are also working on these issues:

  • Vaporless Refueling System – by Industry and the National Technology and Development Program.
  • Saw Specification/Requirements – by the National Technology and Development Program.
  • Training – by Saw Program/Office of Safety and Occupational Health (OSOH)

The NWCG encourages field personnel to continue to report incidents of fuel geysering. Their National Fuel Geyser Awareness page has a link to a reporting system.

STIHL recalls 100,000 chainsaws

(Updated at 1:09 p.m. MST February 24, 2017)

Stihl chain saw MS 461 recall
The STIHL MS 461 chainsaw, often used by wildland firefighters, is one of four models being recalled.

Today the Consumer Product Safety Commission (CPSC) announced a recall of 100,000 STIHL chainsaws that are at risk of fire and burn hazards. The saws being recalled are:

  • MS 461
  • MS 461 R
  • MS 461 R Rescue
  • GS 461 Rock Boss.

The first three are used by firefighters. The last two were not included in STIHL’s official recall notice but a company representative we talked to at the STIHL recall office confirmed they are also on the list.

STIHL Inc. has received 117 reports of pinched or leaking fuel lines but the company reports they are unaware of any damage or injuries caused by the possible defect.

Recalled chainsaws have a serial number between 173092800 and 181993952 under the front hand guard on the engine housing’s sprocket side. The models affected were sold for approximately $1,000 from July 2012 through December 2016.

The recommendation is that owners of the saws immediately stop using them and take them to an authorized STIHL dealer for a free inspection and repair.

STIHL MS 461 R has the added wrap-around handle.
The MS 461 R Rescue
The MS 461 R Rescue has a tool holder, extra large wrap-around handle, chip deflector, and can have an optional depth limiter. It is often used by structural firefighters, according to STIHL, “to access trouble spots, provide additional ventilation, or assist with Rapid Intervention Team (RIT) operations”.
The GS 461 Rock Boss
The GS 461 Rock Boss is for cutting concrete.

MS 461’s are sometimes used by wildland firefighters for constructing fireline and felling trees. This model has been cited in at least one report of a different problem — vapor lock that can result in the engine dying. When the operator removes the gas cap to check on the fuel level, occasionally a “fuel geyser” sprays pressurized gas. This has caused serious burn injuries when the fuel ignites.

Here is a link to the official CPSC recall notice for the pinched or leaking fuel line issue. The STIHL website has a list of seven recalls for various products.

(After calling and talking with the STIHL recall office, the article was updated at 1:09 p.m. MST February 24, 2017 to include two other models of chainsaws that were recalled but not included in the official notice from Stihl and the CPSC. Those two additional saws are the MS 461 R Rescue and the GS 461 Rock Boss concrete saw)

Another firefighter burned by chain saw “fuel geyser”

Last month a firefighter suffered serious burns when gasoline forcefully vented while he was removing the fuel cap on a Stihl MS461 chainsaw.

The incident occurred October 10, 2016 (we first reported it here) on the Pingree Hill prescribed fire near Rustic, Colorado. For years the land management agencies have been warning firefighters about the dangers of gasoline being forcefully released from chain saws. Some of these incidents have occurred with saws that have the new quarter-turn gas caps. After a chain saw has been running for a while pressure can build up in the gas tank causing vapor lock, which can prevent the saw from running. Thinking it may be out of fuel, the operator opens the quarter-turn gas cap and the pressure in the tank forces out fuel and vapor. If there is an ignition source nearby, it can quickly ignite and cause very serious injuries.

Below is an excerpt from a report issued about the October 10 incident. We pick up the narrative as the saw team is finishing a break:

…After roughly fifteen minutes, the sawyer sizes up the second snag and identifies a rock adjacent to the tree that he can stand on to make his cuts. He enters the burned area, steps onto the rock, and pulls on the starter cord. The saw starts but quickly sputters and dies, he opens the choke and tries again with the same result. After two or three more tries he thinks the saw may be out of gas. The saw is equipped with the newer “1/4 turn” quick release fuel and oil caps making it easy to simply flip the saw on its side and open the cap while remaining in a standing position. On older model saws with the threaded caps, this process involved using a scrench to loosen and unscrew the cap, making it difficult to open the tank without setting the saw down.

As he opens the cap the fuel sprays out in two distinct bursts spraying liquid and vaporized fuel on his stomach area and right arm. He quickly realizes this is a very dangerous situation… “I had an oh s*** moment!” The swamper looks, and notices fuel “boiling and bubbling” out of the fuel tank and sees open flame beneath the sawyer’s feet. He yells to the sawyer, but it’s too late. Fuel ignites from the ground, running up toward the saw and the sawyer. Immediately the sawyer’s nomex shirt ignites around his right arm and stomach area. He swings the saw to the left, drops it in the rocks, then sprints downhill through the black to the unburned area beneath the handline and drops to the ground. The swamper reacts and jumps on top of the sawyer and helps extinguish him by throwing dirt on the flames and rolling around to smother the fire.

Once the fire is extinguished the sawyer grabs a radio and calls the Supt. and initially gets no response. He calls the Crew Boss Trainee who responds immediately. The sawyer calmly states “I am burned pretty bad, code red, need an air transport, need to go to the hospital now.”


The patient is in good spirits and is recovering well but did say:

“The one thing I hope comes out of this is that people will give it one last second thought…before you pop the cap”.

The firefighter received 2nd and 3rd degree burns on his right arm and abdominal area.

The report says the extraction of the firefighter went smoothly, thanks largely to the incident within an incident training the crew conducts on a regular basis. About an hour elapsed between the injury and the helicopter taking off to fly him to the burn center.

Two firefighter injuries, a snakebite and gasoline fire

Reports about two notable injuries to wildland firefighters have been released in recent days.

A “72-hour” report provides very little information about another in a series of accidents that may involve a “gasoline geyser”. The document does not include the date of the injury, the location of the accident, or the name of the fire or incident, but it was issued by the Arapaho and Roosevelt National Forest and Pawnee National Grassland headquartered in Fort Collins, Colorado. It is titled “Pingree Hill Chainsaw Incident” and says a firefighter that was working on a prescribed fire sustained gasoline fire burns to the abdomen, arm, and wrist related to a chainsaw while working on a prescribed fire. He was flown to the Northern Colorado Burn Center where he is recovering.

Since at least September 30, 2016 Inciweb has had information about a 2,027-acre “Pingree Hill Prescribed Fire” near Rustic, Colorado that apparently is being conducted on an intermittent basis.

Many injuries have been reported in the last couple of years related to gasoline being forcefully released from chain saws. Some of these incidents have occurred with saws that have the new quarter-turn gas caps.

Here is a video released a year ago on the subject:

The second injury is titled “Rattlesnake Bite” in the Rapid Lesson Sharing report that was released by the Wildland Fire Lessons Learned Center. It happened on the Kent Fire in Montana July 24, 2016. The firefighter never saw or heard the snake that bit him, the report says.

Below are excerpts from the report:

A team of more than five EMTs were assigned to patient care, with one EMT identified as lead caregiver.


Disagreement Involving Interventions and Patient Care

Once the ambulance arrived on scene, there was a disagreement between the ambulance personnel and onsite EMTs involving interventions and patient care being provided. Because of the dispute and increased level of pain experienced by the patient, Division Whiskey decided to transport the patient via the DNRC [Montana Department of Natural Resources and Conservation] helicopter.

The lead caregiver and one other DNRC EMT joined the patient in transit to Baker. The DNRC Task Force Leader followed via ground transport in order to bring the EMTs back once patient care had been transferred.

Upon arrival at the Baker Municipal Airport, the patient was transported to the Fallon Medical Complex emergency room. Medical personnel assessed the bite and cleaned wound.

Because it was determined that side-effects could have adverse effects on this patient, it was decided to hold off on administering antivenin, a biological product used in the treatment of venomous bites and stings. After tissue samples were taken and sent to the lab, it was determined that the bite was nonvenomous.

The patient was monitored and released that evening.

Firefighter injured in Nevada is in critical but stable condition

A Forest Service firefighter who was injured Monday while working on a small fire west of Las Vegas in the Mt. Charleston Wilderness is in critical but stable condition at University Medical Center in Las Vegas.

Josh Evans, a seasonal firefighter, sustained second- and third-degree burns to his upper body when a flash fire occurred during a chainsaw-refueling operation.

When the incident occurred, the firefighter was hoisted off the mountain in a Las Vegas Metro Search and Rescue helicopter, transferred to a Mercy Air medevac helicopter, and taken to the University Medical Center trauma center. He is now in the hospital’s burn unit.

At the time of the injury, the firefighter was part of a crew involved in initial attack on the lightning-caused fire on the Spring Mountains National Recreation Area. After the injury, another fire crew replaced Evans’ crew, and the fire was subsequently contained.

“Our thoughts and prayers are with Josh and his family in this unfortunate situation. We appreciate our selfless firefighters who willingly face ongoing challenges in the interest of protecting life and property,” said Humboldt-Toiyabe National Forest Supervisor Bill Dunkelberger.