A Brief Note of Warning on Fatalities Associated With the Storage of Wood Stove Pellets.

[NNadir]

This one came as a surprise to me, but I stumbled across it while going through the scientific literature this afternoon. Apparently in recent years there have been nine fatalities associated with the storage of wood pellets for wood pellet stoves.

Influence of Oxygen Availability on off-Gassing Rates of Emissions from Stored Wood Pellets (Irene Sedlmayer et al, Energy Fuels, 2016, 30 (2), pp 1006–1012)

From the text:

In times of increasing energy demand, concerns about climate change, and decrease of fossil resources, the attractiveness of alternative fuels such as wood is growing. Wood pellets are high in energy density, easy to handle, and homogeneous in quality.(1) Thus, they are most competitive with fossil fuels for heating purposes among wooden fuel types. Accordingly, the worldwide pellet market has been growing. In 2008 the worldwide pellet consumption was about 10,000,000 tons increasing to 13,500,000 tons in 2010.(2) A statistical report by the European Pellets Council published in 2014 reports the worlds wood pellets production reached 24,500,000 tons in 2013.(3) According to the same report, about 2/3 of the global pellet consumption is attributed to heating. So far, Europe remains the largest pellet consumer market responsible for around 80% of the world’s wood pellet consumption. Estimates of the European Pellet Council further indicate that at least 55% of the European pellet consumption is utilized on the residential heating sector, <50 kW.(3)

Wood pellets are known to emit various gaseous emissions during production, transportation, and storage.(4-9) Nine fatal accidents occurred since 2002 during storage or transportation of mostly big bulks of wood pellets but also in small scale stores.(10) Subsequent investigation indicated increased concentrations of CO, CO2, VOC, CH4,(4, 5, 11, 12) and H2(13) and simultaneous depletion of O2(14, 15) in pellet stores leading to a toxic breathing atmosphere. According to Svedberg et al.(12) O2 declined to levels from 16.9 to 0.8% in closed storages like ocean vessels. However, the concentration of oxygen in ventilated pellet storages strongly depends on the efficiency of ventilation. It can be assumed that in an appropriately ventilated pellet storage room, the oxygen concentration is approximately equal to the oxygen concentration of ambient air.

Reference 10 is here: Lethal Carbon Monoxide Poisoning in Woo dPellet Storerooms—Two Cases and a Review of the Literature (Saskia Gauthier et al, Ann. Occup. Hyg., Vol. 56, No. 7, pp. 755–763, 567755–763 (2012)).

A description of the fatal accidents are found in table 2 of the text. Of the nine deaths, only one was associated with storage in a private home.

My recommendation is that if you're using wood pellet stoves one should store them in a well ventilated space such as a shed or garage that is aerated. They should probably be cycled with the oldest being burned first. A carbon monoxide detector in the area or storage is advisable, particularly if the storage place is confined. It might be wise to store them in a sealed container.

I'm not sure why this is not a problem with the storage of wood for fireplaces. Probably it is related to surface area, since the wood pellets I've seen are small, um, well, pellets.

I have wood burning fireplace in my home with a circulating air fan to heat my home. In recent years I've been less and less inspired to use it - even though I use downed wood from trees on my property that would otherwise rot releasing carbon dioxide - since I am aware that about half of the seven million air pollution deaths that take place each year are from the combustion of biomass, particularly indoors. My home is regrettably heated by dangerous natural gas which is less of an air pollution source than wood, at least in a purely chemotoxic sense, but noxious all the same in a climate sense. About 50% of the electricity supplies in my state is for the time being supplied by nuclear energy, so when possible I do use electric space heaters.

(I'm not sure we're going to have all that many winters in New Jersey in the future, since we bet the planetary atmosphere on so called "renewable energy" with the result that the rate of climate change driving carbon dioxide releases is rising, not falling. So called "renewable energy" didn't work, isn't working and won't work.)

But in any case, if you have a wood pellet stove, be safe.

Enjoy the rest of your Sunday afternoon.

[hatrack]

1. Whiskey. Tango. Foxtrot.

Wow, I would never have guessed that as a hazard in a million years.

Interesting - and thank you!

[NNadir]

3. I was very surprised myself. On seeing it, I emailed some family members who I know use pellet...

stoves.

I'd feel horrible beyond belief if I'd become aware of this and said nothing.

Probably the risk is relatively small compared to the risk of getting lung cancer from burning biomass, for example, but on the other hand, it's a safety issue of which people should be aware. It's quite possible that some fatalities have not been recorded, since even mild carbon monoxide related hypoxia can lead to heart attacks. If I recall correctly from my readings on this topic, many of the mechanisms for fatalities related to air pollution do in fact, involve this mechanism. Air pollution deaths, like smoking deaths, are not entirely about cancer.

You're most welcome. Thank you for your attention to issues in the environment. You're a real serious news source.

[matt819]

2. Had no idea

I use kiln dried firewood on my wood stove. First, not much is stored in thehouse st any one time. It's in the wood shed or under tarp. So there's that. Also, I'm wondering whether the rejTivrly minimal processing of firewood reduces the chance for fumes of any kind.

[NNadir]

4. I suspect that pellets are much more prone to this effect than wood.

This is unquestionably related to surface area. Firewood simply doesn't have the same exposure to air that pellets do.