This is what landed me in A and E at seven this morning...
Last night there was a long power fail here which entailed the forum database server running on UPS for an extended period. The server and it's peripherals, because it runs unattended for long periods is equipped with a Fire Protection System designed to cut power and extinguish any fire should the server or UPS do its worst. The extinguishant is stuff called FM200 with is fully non-toxic, non ozone depleting and so on. It's an HFC (heptoflouropropane) compound. It is so safe it is used, as HFC2207, as a proplellent for asthma inhalers.
Anyway, as a possible result of the UPS running for an extended period on batteries and the UPS running hot (as it does under those conditions) the fire system decided to trigger itself at 04:30 this morning and release its extinguishant. It's non-toxic so no worries. It even extinguished my central heating pilot light so it works...
I vented the house and proceeded to toast some crumpets under a gas grill. During the toasting, the kitchen filled with the most awful, pungent, sharp smell that got your throat somewhat.
Checking the MSDS for FM200, I found that if the released gas is heated in a naked flame it liberates Hydrogen Flouride which is nasty enough and I had a kitchen full of it. Worse though is that on contact with water, Hydrogen Flouride becomes Hydroflouric Acid that this is truely nasty, nasty stuff..
here is a description of it's toxicity:
Hydrofluoric acid is extremely corrosive and a contact poison. It should be handled with extreme care, beyond that accorded to other mineral acids, in part because of its low dissociation constant, which allows HF to penetrate tissue more quickly. Symptoms of exposure to hydrofluoric acid may not be immediately evident. HF interferes with nerve function and burns may not initially be painful. Accidental exposures can go unnoticed, delaying treatment and increasing the extent and seriousness of the injury. HF is known to etch bone, and since it penetrates the skin it can weaken bones without destroying the skin. More seriously, it can be absorbed into blood through skin and react with blood calcium, causing cardiac arrest.
In the body, hydrofluoric acid reacts with the ubiquitous biologically important ions Ca2+ and Mg2+. In some cases, exposures can lead to hypocalcemia. Thus, hydrofluoric acid exposure is often treated with calcium gluconate, a source of Ca2+ that sequesters the fluoride ions. HF chemical burns can be treated with a water wash and 2.5% calcium gluconate gel or special rinsing solutions. However, because it is absorbed, medical treatment is necessary — rinsing off is not enough. In some cases, amputation may be required.

Time for a visit to A and E...
Hydroflouric Acid is often liberated in car fires and hence the reason to approach a burned-out car with extreme caution.