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.

Sawyer mentorship

The Information officers on the Sawmill Fire in Arizona created this article and the photos. Not only does it give the outside world a peek into what wildland firefighters actually do (in this case while at the incident base) but it illustrates a great example of firefighters from the Globe Hotshots offering assistance or mentoring others when they have the time on a fire assignment. Firefighting of all types, structure and wildland, is a close-knit community and firefighters will help each other out even if they’re seeing each other for the first time, and knowing they may never meet again. Good job, Globe Hotshots and Wendy Koinva.


When Wendy Koinva started running a chainsaw, the guys on her crew told her it needed a name. “Give it a manly name,” they said. Wendy had another idea.

During the summer, a wildland firefighter spends thousands of hours carrying their pack, swinging their tool, and sleeping in their sleeping bag. Taking ownership of their things is important. If they take care of their gear, then their gear will take care of them. Sawyers have one of the most important and challenging jobs on the fireline. They are often in front, stomping through brush – clearing a safe way for their coworkers, their brothers and sisters, their buddies. If a sawyer is hungry and their saw needs gas, the saw gets fed first.chainsaw mentor

Wendy is a member of the Pima Type 2 Initial Attack Crew which is part of the Salt River Agency Tribal Nations Response Team. She’s been with the crew for two fire seasons. Her coworkers noticed her take an interest in running a saw. They suggested she take part in the tradition, among wildland sawyers, of naming her saw. It’s a way of taking ownership and pride in the job that they do. Wendy chose Pööts’tima, which is Hopi for “Stomping Bear,” because that’s how she sees herself and her saw. They are out in front, ahead of the crew, stomping through the brush and clearing the way.

While Wendy and Pööts’tima were “stomping” the Sawmill Fire, they came across the Globe Hotshots, led by Dean Whitney. Hotshot crews are elite. Hotshot sawyers are among the best at what they do. When Dean heard about Wendy and her saw, he recognized an opportunity for cross-agency mentorship. He invited her to come over to the crew’s buggies for a lesson, and worked with her on maximizing her and her saw’s potential.

Wildland firefighters value duty, respect, and integrity. We can all take a lesson from Globe, Wendy and her Stomping Bear.

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)