Detection of Tungsten Hexafluoride I'll be doing some work (as a software engineer) with a vacuum process chamber that consumes various nasty gases.  There are numerous safeguards in the system, but as a cautious type, I decided to read the MSDS of the chemicals involved.  The one that makes me the most nervous is tungsten hexafluoride; one mole apparently reacts with water to form 6 moles of HF, which I distantly remember from chemistry class as being bad news.  Being largely composed of water, I find this troubling.  If there were failures in the multiple safeguards and a leak did somehow occur, how could it be detected?
$\ce{WF6}$ is not an uncommon gas used in industrial manufacturing of semi-conductors. Commercial gas detectors are readily available, and will detect $\ce{WF6}$ down to low ppm range, which is about an order of magnitude less than the $\mathrm{LC}_{50}$ for rats, apparently.

You could google tungsten hexafluoride detector, but some examples include (no affiliation or endorsement):


http://www.newcosmos-europe.com/gas-by-name/144-tungsten-hexafluoride-detection.html 
http://www.toxicgasdetection.co.uk/gas/?gas=Tungsten%20hexafluoride&amp;search=Tungsten%20hexafluoride&amp;form=gas&amp;id=416 
https://www.gas-find.com/hexafluorure-de-tungstene.html 


The most common type of detector is a diffusion monitor with electrochemical sensor.
Some sensors actually use conversion of $\ce{WF6}$ to $\ce{HF}$, and then detect the $\ce{HF}$. Commercial $\ce{HF}$ detectors at low ppm range are also common.