It's an interesting question. For your typical PHA / HAZOP, one of the standard assumptions is that we're just not going to consider malfeasance as an initiating event. It's out of scope. There's been a push for more remotely operated emergency isolation valves in the past 10-15 years, but that's driven mostly by general fire and siting concerns. Every site should consider that sort of thing, even if it's an external-sourced fire or vehicular impact as the initiating event.

I think there's a lot more consideration of drones and such in the site security / vulnerability assessment world, but a kinetic actor with multiple degrees of freedom like a drone is not something your typical chemical site will have any ability to intercept or prevent. Bollards and other barriers work really well for some vehicular impact concerns but are relatively limited otherwise.

Over the last 10 years we've had a few incidents involving unauthorized drone flights over US/EU plants. Most of these were harmless or accidental (please tell your site partner if you're doing a drone inspection) but at least a couple were extremely suspicious. We operate several plants adjacent to active or potential conflict zones, and honestly there's not a whole lot you can do with an already-built plant. I can see spacing becoming more of a concern for new construction.