There are a great many powerful toilet cleaners and other household chemicals intended for oither purposes. Not surprisingly, it is all too common that despite the written warnings householders and others mix incompatible products in often ridiculously large quantities, stand over the bowl with brush in hand, and then get the shock of powerful haxardous valour releases or a violently exothermic reaction. Most contract lceaning companies and other professionals, for example in swimming pools and spas will face this problem and specify only compatible cleaning products on site. Inevitably, it goes wring from time to time, ofetn with spectacular resyltys and a great many casualites.

Only "SDS" I can find is an incomplete one via B&Q pages. Seems the product is enzymatic. Doesn't say what the carrier/pH is though. Google attempts at finding proper MSDS now thwarted by the number of 'hits' on the incident.

Thanks ahoskins, Better SDS than mine on google,however,cannot see how this is so reactive with only two drops of the stuff !!! Regards,Paul

Yes Ron, I didn't read the data on the sheet very well, but it could well be the same product in a different form. Dr Drain is a registered trade mark it seems. However, if a 'couple of drops' has this effect, the risks are being serioulsy understated. I haven't seen the packaging warnings (if any). We don't know the whole story of course - it could be that caustic soda had been used previously to unblock the drain, there might still have been a residue present. Just guessing now of course...