Your question is a fairly simple one but it appears every answer you have been given so far are a tad extreme.
I wouldn't coat in silicone as this has a fair amount of solvents in and is prone to outgassing which coldcould give false gas leak readings.
To completely mitigate the risk of a spark and outgassing, coat your assembly in Parylene C. thisThis conformal coating is guaranteed to give you the results you want.