Question: In Shadowrun 2nd Edition, damage for grenades decreases from `10S` in power level by 1 per meter for offensive grenades and by 1 per half meter for defensive grenades. The book gives an example to illustrate this on page 97 saying

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> a target standing three meters away from an offensive grenade blast would be subject to a base 7S damage, while a target standing six meters away would be subject to a base 4S damage.
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Blast effects for other kinds of explosives aren't described on this page.

The ratings for Plastic explosives is listed on page 257
[![enter image description here](https://i.stack.imgur.com/6KeRh.png)](https://i.stack.imgur.com/6KeRh.png)

Damage for Plastic explosives is described on page 242 as being the rating of the explosive with a severity of `D` so for example 1kg of Plastic, Compound XII would have a damage of `12D`.

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> The Damage Code is (Rating)D per kilogram.
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The page goes on to explain how the damage is reduced the further from the explosion the target is.

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> The Power of the blast is reduced by the base Rating per meter.
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Does this mean that 1 meter away from detonating 1kg of Plastic Compound XII the damage is `12D` and 2 meters away it's `0D`? This seems unlikely given how different "-12 per meter" is from the "-1 per meter" for grenades.

How do you calculate damage from Plastic explosives at a given distance from the explosion in Shadowrun 2nd Edition (2e)?

Answer: 
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> Does this mean that 1 meter away from detonating 1kg of Plastic Compound XII the damage is `12D` and 2 meters away it's `0D`?
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No.

Let's go back to your grenade example, where the damage at a distance of 3 meters is reduced from `10S` to `7S`. This tells us that the reduction in Power applies *even for the first meter*. Therefore, 1kg of C-12 would have a damage code of `12D` at the point of detonation, which then drops off to zero at a distance of 1 meter, not 2 meters.

I gather from the tone of your question, as well as your comment on Trish's answer, that you find it surprising that plastic explosive blasts fall off so incredibly quickly compared to grenade blasts. This is, however, entirely appropriate (and most likely intentional) because the designed purpose of a grenade is to direct its blast energy outward over a large area, while plastic explosives are intended to generate a *contained* blast, suitable for destroying a specific target point without causing excessive collateral damage in the surrounding area. If you're trying to crack a vault, you want something that's powerful enough to blast through the lock, but doesn't also level the entire building.
Shaped plastic explosives are designed to only damage the target and not much else. The simple formula makes it easy to determine minimum safe distance - since the damage is Rating times Kilos, and the damage fall off is Rating per Meter, those explosives don't normally damage anything more than Rating meters away.

Please note that if you have pallets of commercial grade explosives weighing enough that you need heavy machinery to move them, and within that blast radius are *more* similar pallets, the blast range will still be *significant*. I had a player long time ago on a job to sabotage a warehouse crane who decided to see if he could get a bonus by putting timed explosives in some of the pallets in the warehouse on the way out. He probably should have checked what was in them when setting the timers. He did not receive the bonus he was hoping for; his next character, however, checked the labels on crates before randomly blowing them up. (He still randomly blew them up, though.)