Hydrochloric acid is corrosive and can pose a health and safety threat if not handled properly. Hydrochloric acid can be dangerous both when inhaled, or from direct skin contact.

How to dispose of hydrochloric acid

Protocols for disposal of hydrochloric acid may vary by state, and therefore you should always check within your local jurisdiction. Some states may allow you to pour dilute hydrochloric acid down the drain, while others require that it first be neutralized. For household use, it may be appropriate to simply dilute hydrochloric acid by adding acid to water. Remember as a general rule, always add acid to water and not the other way around. To neutralize hydrochloric acid, you may add a cheap and accessible household base such as sodium bicarbonate (baking soda). Together the acid and base react to form innocuous salt and water, which can safely be poured down the drain. It will become apparent that the reaction is complete when the fizzing and bubbling has ceased. For maximum safety, both of these steps can be performed in succession – first dilute the acid to minimize safety hazard, and follow with the neutralization step. If these protocols are followed to completion, the resulting solution can easily be safely disposed of.

For larger scale operations, including small businesses, we follow the same exact principals. However, in this case, proper disposal of hydrochloric acid becomes more critical from a safety standpoint because of the larger quantities of hazardous material.

For best practice, highly concentrated industrial grade hydrochloric acid should first be diluted. Again, always add acid to water. Also ensure that you are wearing the appropriate personal protective equipment, including goggles and fully covered skin. Latex gloves are recommended to prevent the strong acid from coming in direct contact with the skin.

Neutralization is an important step for waste disposal because it converts hazardous, reactive chemicals into harmless salt and water. Neutralization occurs by reacting an acid and base. In the household example, we used a common household base, sodium bicarbonate, or baking soda, because it is easy to find and keep on hand. For larger scale operations, a more economically viable option will be necessary, but most bases will do. Some examples of bases that can be used for neutralization include:

• Sodium hydroxide
• Calcium hydroxide
• Magnesium oxide
• Ammonia
• Sodium bicarbonate

The reaction should be performed in an acid-proof vessel designed to hold concentrated hydrochloric acid. As before, you will observe a bubbling and fizzing that indicates the reaction is taking place. For best practice, you should also monitor the pH of the reaction mixture with a pH meter or pH paper. The reaction is complete when the pH rises to 7, or neutral, and you should stop adding base at this point. If performed correctly, the resulting solution is no longer considered hazardous waste and can be disposed of normally.

Always check with the chemical waste disposal guidelines in your local jurisdiction to be sure you are complying with regulations in your area.

Lab Alley is pleased to provide you with the highest quality hydrochloric acid in a variety of concentrations, technical grades, and sizes, including bulk sizing. We also supply a selection of bases to help you carry out the neutralization reaction.

As always, if you have questions about hydrochloric acid or any of our products, please feel free to contact us for more information.