You might want to check with Atlas Copco re the characteristics of the tool case. Although it is plastic, it could have been formulated to be dissipative.
Unfortunately, with power tools there is always the conflict between the need to isolate the user from the AC power and at the same time prevent component damage. Ionization could also be used to reduce the potential if there are not direct grounding alternatives.
These are suggestions of a training specialist, however, not an ESD engineer. If you need further contacts on this, you could contact me offline, and we might be able to find a real authority.
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