The following is a presentation delivered by Dr Tom Baster at the Brisbane Biodiesel Meet and Greet 1 on the 11 June 2006.
Making Biodiesel is a relatively simple procedure well within the capabilities of many Australians who have a long tradition of having "a go" at fixing, making and repairing things. However there are safety aspects involved that should be considered before making biodiesel to avoid any potential health problems.
There are two main areas of concern - these are:
- Acute injuries
- Chronic exposure to low concentration of chemicals - I am not really going to address this
General workshop safety:
Apart from the obvious hazards in a workshop (inadequate ventilation, fire, chemical burns), making BD involves the use of a couple of toxic chemicals. It is incumbent on us to store these chemicals in a safe manner - such that access to them is denied to young children and they are stored with regard to potential fire and explosion hazard - this mainly refers to methanol which needs to be well ventilated to prevent any build up of fumes that could be ignited with a resultant explosion. There are regulations and insurance issues involved in storing chemicals as well but this is outside my discussion.
Another workshop issue involves the lifting of heavy drums or containers. Most of us intuitively recognize when an object is too heavy for us and get assistance or use a mechanical device, but the main hazard is intermediate weights that we think we can manage ok - for most people this is in the range of 10-20kg ( maybe up to 30kg for young males). Especially if our back muscles are already somewhat fatigued, lifting of these weights with a turn or reach at the same time "unlocks" some of the support mechanisms in our lower back with resultant excessive strain on other structures ( especially discs) which can result in an injury. So beware the weight that looks manageable.
A further issue that many people are unaware of is the safe storage of damp or oily cloths. There is a potential for auto combustion of piles of damp/oily cloths and there have been fires in the past from this. It is a good idea not to have piles of damp/oily cloths or to store them in a metal rubbish bin with a lid.
The final issue with regard to general workshop safety is the safe disposal of any waste chemicals. There are usually Council regulations regarding the dumping of surplus paint etc and I leave this up to each individual to determine how to dispose of waste wash water and glycerine -the main byproducts of our biodiesel production.
Sodium Hydroxide - NaOH and Potassium Hydroxide KOH
The first main chemical to address is NaOH - but the comments also apply to KOH
This chemical is a strong alkali and burns our tissues worse than acids - we have a natural mechanism to buffer acids somewhat but alkalis are not handled as well by our body tissues.
In Victoria in 1998 ( sorry no figures for Qld or more up to date figures) there was 1200 admissions of children less than 5 years with poisoning - most of these were for paracetamol or mothball type substances - about 14% (168) were for "corrosives" - and many of those were acids rather than alkali. So, in perspective, not a major problem but nonetheless none of us want to have a child access and swallow any of our Na OH.
Splash or contact onto skin - no major problem if aware this has occurred -wash thoroughly (for at least 15 minutes) until the skin feels normal - ie loses the soapy feel that is a result of the Na OH converting some of our subcutaneous fat into soap. Mostly, there will be no obvious injury. However if a burn type lesion results- redness/loss of skin or ulceration occurs a trip to see your local GP is probably in order.
Splash or contact into eyes - much more serious - wash thoroughly under a tap for at least 10-15mins -try to keep the eye open as the water flushes the cornea. After this, a trip to your local GP or hospital emergency centre is mandatory to check for corneal damage - hopefully there will be no long term damage but it does need to be properly assessed by the doctors.
Inhalation of fumes - this will tend to cause coughing, wheezing, or shortness of breath. Obviously remove yourself from the fumes and mostly the symptoms will settle. A couple of puffs of Salbutamol (Ventolin, Asmol inhalers) would usually be quite safe if you have access to this medication if symptoms don't rapidly settle. In severe cases of respiratory distress a phone call to the QATB (ambulance) is in order for them to attend and provide oxygen and (probably more) Salbutamol before taking you off to hospital.
Ingestion - probably accidentally swallowing a small flake or granule will only cause some local redness somewhere in the tube from the mouth to the stomach and apart from being a bit painful there should be no long term problem. Drink plenty of water. However a significant amount - eg a child swallowing a mouthful - is serious and needs urgent hospital care. (If person is conscious) First aid is to give plenty of water ( mix up a weak vinegar drink as this will help neutralise the alkali) and do not induce vomiting.
Thus Na OH - prevention - butyl rubber gloves, and a full face mask will prevent just about any chance of injuring yourself with this chemical. First aid - water to flush the chemical - plenty of quantity and flushing time
Methanol
This chemical is a real concern in terms of fire risk and exposure
Methanol boils at 65*C and burns without a flame. It is explosive at vapour levels of between 6-36%. Make sure you have a well ventilated space and beware of methanol boiling.
Methanol is not toxic as such to humans - we actually make a little ourselves each day and some of our foods have methanol in them. For example 30 L of orange juice has a toxic amount of methanol and it occurs in many alcoholic beverages along with the more familiar ethanol. The problem with methanol is the toxic metabolites formed - these include formaldehyde and formic acid
A safe daily amount is about 1-2mls. A toxic amount is about 8mls (although some sources state 15-20mls) and a fatal amount is only 100mls. These figures are only approximate. The half life - ie the time it takes to metabolise and eliminate Methanol is about 24-48hrs. It is readily absorbed through skin, lungs and eye tissues. Immediate ( a few minutes) after absorption you can get a similar effect as from too much ethanol - light headed, confusion, nausea and abdominal pains.
This usually settles and then after about 1 day the effects from the toxic metabolites occur of which the most serious (excluding death!) is visual problems including blindness.
However - if it is recognized that an overdose of Methanol has occurred there is treatment available that will largely prevent any long term damage. This involves ethanol to help block the metabolic pathways and thus stop any buildup of formic acid and another compound called fomepizole which also inhibits the metabolism of methanol.
Splash in eyes - wash with water - probably less than a toxic amount would be absorbed. If eye painful a visit to your GP or hospital for an eye check is reasonable.
Contact with skin - wash off with plenty of water. Probably less than toxic amount. If uncertain of amount visit your local hospital emergency centre
Inhalation of fumes - treat as for Na OH - fresh air and some salbutamol if available. Severe respiratory distress call the ambulance for further treatment
Ingestion - depends on amount- a splash of a few drops in the mouth - probably safe but quantities more than 5-10mls needs hospital assessment.
Prevention of Methanol injuries - gloves as for Na OH , a full face mask
However avoiding fumes is more difficult for the backyard biodiesel maker -
Most available masks do not filter out fumes. There are solutions to this but they are expensive and with a little common sense - ie closed processors or avoiding breathing whilst decanting methanol the problem of inhaling toxic amounts of methanol fumes can be avoided.
Methoxide
The mixture of Methanol and Na OH is an exothermic reaction- ie releases heat and creates some pressure. Obviously one needs a container that can vent pressure and does not explode or melt when the reaction occurs. In terms of the effect of methoxide on human tissues , the comments on methanol are probably the most pertinent and simply avoid inhaling any fumes or spilling any onto exposed skin and wear a full face mask to avoid any splashes into eyes.
Biodiesel
Once we have made our product we now have a very safe liquid - any splash into eyes would still need to be washed out but a spill onto skin or a few drops in the mouth is not really a health risk It is stated that Biodiesel is 10 x less toxic than salt but I am sure no one really wants to test that personally!
Conclusion
Whilst Na OH and Methanol are toxic chemicals, the backyard biodiesel maker can fairly easily avoid injuries. If contact with skin or eyes is made plenty of water is the best treatment before deciding on anything else. This talk is only really my opinions as a GP- no doubt there are others who would dispute what I have stated and I have no doubt missed out some important points.
The take home message is :-wear long sleeves, trousers, closed shoes, butyl rubber gloves, and wear a full face mask to stop any splashes.Also avoid inhaling fumes as much as possible. With these simple measures hopefully you can enjoy a long and productive life making Biodiesel.
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Diesel-Tech