So, I've been trying to cook up a demolitions/grenades focused character. And I heard a rather interesting take on it, essentially saying that while they're useful skills, the reputation of someone who routinely uses bombs and fire and gas and etc to solve their problems is going to take a nosedive rather quickly.
On the bright side, there are only so many RAW ways to gain notoriety. Depending on the overall results, toxins, arson, and explosives may only count towards "pissing off a Johnson" and "incredibly obnoxious behavior", but there's a risk of "getting arrested", "killing an innocent" (or dozens of them), "earning a powerful enemy", and/or "exceptional bad luck".
Bombings are an excellent way to Send A Message, to Whomever May Be Concerned. They do draw investigative attention from law enforcement, governments, journalists, "concerned citizens", etc., to a facility that might not stand up to such scrutiny. Booby traps hopefully draw such attention to personnel that might be similarly shady. On the other hand, using a pound of C4 to open a locked door, when a crowbar is safer, faster, and quieter, screams "Amateur!" or "Psycho!".
Runners with a chemistry background also tend to be the maniacs who like to cook their pyrolytic homebrews in the basement, or kitchen, or bathroom of your team's safe house. Eventually, they're going to glitch on that chemistry roll, and here come the Feds.
Fire. Well, any magician or shaman that can summon a fire spirit generally will, at which point it sucks mightily that most impact-resistant armor is made of plastics. It's a traditional way destroying paper records (immune to cyber skills!) - explosives may just scatter them. It's also a more horrific way to die than Joe the Security Guard signed up for. Like explosions, fire where fire isn't expected draws investigative attention.
Any runner working with an arsonist who gets off on watching buildings burn down with people inside has to wonder when and where the next victim(s) are coming from. Still want to share your safe house with them?
Toxins and drugs boils down to chemical warfare: incidental casualties at best and intended casualties at worst, and these are the things that scare people the most because they never know when the hammer's going to fall on them. (RL example: my fellow TA/lab partner considered hiding his coffee cup when one of the reagents for my thesis work turned out to be just as black, and entirely soluble in water, as coffee. Going by the LD50, it was also one of the
least lethal chemicals in the chem cabinet.

)
At one time or another, someone's liable to glitch and spill something while hand-loading their capsule rounds, splash grenades, or splash mortars. Such chemical spills may well fall under the "Concentration" rules on p. 255. Do take a minute to read them and then reflect on how many combat turns there are in 2-10 minutes.
UNlike explosives and fire, team members or innocent bystanders walking in on a lethal indoor spill before dispersal/oxidation is complete, may be unaware of a problem until the toxins take effect and it's far too late.
So ... it depends. Like magic, careful application of these tools in the appropriate setting is a good thing, just remember to check for tracer tags and to cover your tracks.