ECN Forum Forums Safety Discussion and News Safety News and Product Recalls Use lightening arrestor for Oil tanks in on shore oil field is safe or hazardous?

As per legislation on use Electricity, it is mandatory to provide Lightening arrestor by earthing the oil tanks in on shore oil fields.
In a few cases, it has caused fire because of Lightening strike. Is this due to faulty design of Lightening arrestor considering the zone of protection or the provision of lightening arrestor has caused the least path for the current to flow and create spark due to lightening?