Biodiesel methanol is highly volatile. Biodiesel in its finished form is actually totally safe and non-toxic. It has been classified as safer than salt, so there are no safety restrictions for the storage of biodiesel.
The methanol is what goes into creating biodiesel, and it is extremely dangerous. All chemicals or components that are used in the making of biodiesel have Material Safety Data sheets regarding their behavior and treatment. You should always store methanol away from anything flammable and in a cool dark place. Ideally the drum in which you store your methanol should have a double skin or be a double container.
Methanol ought to be grounded. Not the methanol itself, but the drum in which you store it. It is strongly advised that you ground it to a copper stake in the ground and the drum should be bonded to its container.
As methanol is a highly toxic poison it is always advised that you should wear a safety mask when dealing with it. During the biodiesel production process, specific safety measures are always adhered to, so if you adopt the same form of safety you will remain unharmed.
Salvaging any un-reacted methanol is called biodiesel methanol recovery. This is an optional process, but manufacturers do use it. It is one of the many stages involved in the making of biodiesel and you should always wear gloves, safety glasses, a mask and apron, to protect as much of your body as possible. Any fumes should be prevented from entering your lungs. If you wear a mask or respirator you have a better chance of not inhaling any dust which could be carrying particles.
