I'd like to revisit Scope of unsuitable questions to include security and hazardous flags in light of a question that came up today and elicited some controversy.

The question in question is How to increase the concentration of HCl.

There were some strong reactions and flags indicating that having the information about this procedure "out there" is potentially dangerous, though both commenters and those answering did address some of the safety issues.

I'd like to revisit how we should police these, if at all. The question at hand wasn't asking for explicit instructions on how to do something illicit, and certainly has academic value, but at the same time, in the hands of the user asking (or anyone finding this question via search), such a procedure could put them in danger.

Are we overreacting or under-reacting to this type of content?

  • $\begingroup$ The closest to this I can find is On allowing malware-related questions on meta.SO. The result of the discussion was that it's dangerous knowledge for sure but we can't control how it's being used and we should just go ahead and answer. As MadSci points out in his answer, they'll find another venue to find out how to do it. Best if it's us and if we make sure somebody tells them the dangers. $\endgroup$
    – M.A.R.
    Commented Mar 5, 2017 at 8:02

2 Answers 2


I don't think not answering this kind of question at all would be useful. The information is out there, and the asker will most likely just use another resource if we shut them down here.

But I do think that our responsibility is greater when answering questions by amateurs with limited expertise and equipment. We should not answer without explaining the dangers in those cases.

The current top answer has a warning about proper precautions, but for me personally that is far too weak and general. Especially since the asker mentioned using an isolated system to prevent HCl from escaping, and amateur might just get the idea to heat HCl in a closed apparatus, with the inevitable disastrous result.

A good answer should explicitly list the required safety procedures and equipment, and mention the dangers if anything goes wrong. Hopefully this woudl discourage the asker from performing the experiment if they don't have the experise or equipment for it.


Assuming we're happy that the question isn't asking about some illicit synthesis where laws are clearly being broken (*), then I see no reason why chemistry.se has any more of a responsibility/duty of care towards the person asking the question than any other resource on the internet.

Chemistry journals are full of procedures which are likely to cause harm in the hands of a junior chemist/without careful consideration, yet articles/supporting information documents rarely detail safety hazards/precautions, unless the hazard was particularly unexpected or out of the ordinary. (That said, I'd accept that journals are generally written by experienced chemists, where as on chemistry.SE there is an element/possibility of the 'blind leading the blind', that is inexperienced chemists/non-chemists/old-school chemists offering practical advice to other inexperienced chemists who don't know better).

If we do feel the need to police these sorts of questions, then perhaps the most productive thing would be to adopt an 'org syn' style disclaimer, basically telling the person asking the question to not take the response at face value but rather consider the implications of what they're being told to do (see below). I'm not sure how this could be implemented; either as part of the T&C's during signup, or perhaps something the mod's could tag to specific posts related to practical chemistry.

The procedures in Organic Syntheses are intended for use only by persons with proper training in experimental organic chemistry. All hazardous materials should be handled using the standard procedures for work with chemicals described in references such as "Prudent Practices in the Laboratory" (The National Academies Press, Washington, D.C., 2011; the full text can be accessed free of charge at http://www.nap.edu/catalog.php?record_id=12654). All chemical waste should be disposed of in accordance with local regulations. For general guidelines for the management of chemical waste, see Chapter 8 of Prudent Practices.

In some articles in Organic Syntheses, chemical-specific hazards are highlighted in red "Caution Notes" within a procedure. It is important to recognize that the absence of a caution note does not imply that no significant hazards are associated with the chemicals involved in that procedure. Prior to performing a reaction, a thorough risk assessment should be carried out that includes a review of the potential hazards associated with each chemical and experimental operation on the scale that is planned for the procedure. Guidelines for carrying out a risk assessment and for analyzing the hazards associated with chemicals can be found in Chapter 4 of Prudent Practices.

The procedures described in Organic Syntheses are provided as published and are conducted at one's own risk. Organic Syntheses, Inc., its Editors, and its Board of Directors do not warrant or guarantee the safety of individuals using these procedures and hereby disclaim any liability for any injuries or damages claimed to have resulted from or related in any way to the procedures herein.

(*) It's often very clear when people are asking about drug syntheses due to the very specific nature of the chemicals involved. In these cases I fully agree that answering is counter productive anyway, irrespective of safety.


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