Alkylate and ready-mixed saw fuel: what a safety forum, a study and the exposure tables say

This page reports what three documents and one maker page say. It is not medical advice and it does not say which fuel to use. The regular fuel mix ratios and ethanol statements are on the page about chainsaw fuel mix and ethanol, and storage and container rules are in the guide to fuel cans and fuel storage.

What the Forest Industry Safety Accord bulletin says

The Forest Industry Safety Accord (FISA) issued Safety Bulletin 03.18, dated June 2018 and titled to say that alkylate fuel fumes are less hazardous to health than benzene fumes, makes these statements:

Chainsaw exhaust fumes, breathed in by the operator standing behind the exhaust, can cause irritation of the nose, eyes and lungs, headaches and dizziness.
An alkylate petrol was introduced in Scandinavia in 1988 to reduce this health risk, and in Scandinavia, it says, this petrol is as important as putting on chainsaw trousers.
Alkylate fuel does not contain benzene, which the bulletin calls a known carcinogen, and it contains virtually no aromatic hydrocarbons.
It can be bought ready mixed with biodegradable two-stroke oil, which the bulletin says removes the risk of spillage when operators mix their own fuel.
The bulletin says the benefits include a longer shelf life and machinery life, and that alkylate can be stored without deterioration.

The bulletin also gives percentage figures for emissions and for the aromatic content of regular petrol. It names no method or test for them, so they are not repeated here. The bulletin ends with the web address of a stockist.

What the 2016 study found

The study "Determining exhaust fumes exposure in chainsaw operations" by F. Neri and colleagues appeared in Environmental Pollution, volume 218, 2016, pages 1162 to 1169. The abstract on the Palermo university repository says its aim was the inhalation exposure of forest operators to polycyclic aromatic hydrocarbons (PAHs) and BTEX, which stands for benzene, toluene, ethylbenzene and total xylenes, in chainsaw exhaust. It was done in four kinds of forest work: coppice clearcut, conifer thinning, conifer pruning and sanitary cut. Three fuels were used, a normal two-stroke petrol mix and two alkylate fuels, and eighty personal air samples were collected.

The abstract reports these results:

None of the four kinds of forest work significantly changed the PAH and BTEX exposure.
The fuel type made statistically significant differences. PAH and BTEX exposure was generally one order of magnitude lower with modern alkylate fuels than with the traditional oil and lead-free petrol mixture.
The small differences between the two alkylate fuels were not statistically significant.
The authors state that while forest workers are exposed to PAHs and BTEX, the maximum values are generally well below accepted occupational exposure limits.

The benzene limit in the HSE table

HSE's publication EH40/2005, fourth edition 2020, lists workplace exposure limits under the Control of Substances Hazardous to Health Regulations 2002. The benzene row gives CAS number 71-43-2, a long-term limit over an 8-hour time-weighted average of 1 ppm, which is 3.25 mg per cubic metre, no short-term limit, and the notations Carc and Sk. The table's comment column says these notations are not exhaustive. The row shows what a workplace exposure limit looks like in Great Britain. The study abstract states no measured values, so the two cannot be set side by side here.

One maker on its ready-mixed fuel

One saw maker's UK page on fuel mix, dated June 26, 2025, describes the maker's own ready-mixed fuel as formulated for its tools, with a long shelf life and a stated storage time of up to 5 years. It calls that the reliable and easy choice. The same page says a fuel mix made by the user may no longer be fit for use after 30 days of storage. These are statements by a maker about its own product. The page does not use the word alkylate.

What these sources leave out

None of the four sources names a regulator that recommends or requires alkylate fuel. The sources give no price figures and make no comparison between brands.