1/ you will need to up your insurance.
2/ petrol stations have haz management conditions to comply with, they normally insist that all sites are sealed with top notch sealer, this is part of the haz regime,
3/ you will probably find that haz management says that you cannot run pumps etc unless designed for use on this type of site, therefore you will need to be able to hose up to work from a non haz distance.
4/ if it proves that you have to seal, look at the problems
a/ you wash, it has to dry before you can sand, how will you keep the area clean till it drys, for sanding.
b/ same again for sealing.
5/ you will probably find that you cannot work on your own on a site like this out of hours due to hse/ haz regs
This is the advice i was given by one of the guys on another forum. most people said somewhat similar
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