Here's a very good article about the dangers of static electricity when fueling aircraft. There are some risks here discussed that I had never heard, so I found the article very useful.

From the article: Always remember these key points:

• Refuel and defuel outdoors
• Ensure electrical bonding is in place prior to removing any fuel caps
• Use only approved containers
• Use only approved filters
• When in doubt, consult your fuel supplier.

Also, it seems using a chamois to filter the fuel can greatly increase static electricity buildup.

Here is a link to the PDF: http://www.caa.govt.nz/fulltext/vector/vector_05_5_sept_oct%2005.pdf