In answer to GBC questions, the Government said the chemicals were being stored in direct sunlight after a delay in their transportation to Spain for disposal. The exposure caused the containers to leak, and the mixing of the two substances led to a chemical reaction.
The incident was quickly dealt with by the fire service, with police closing off the area.
The risk was deemed moderate due to the small quantities that leaked.
A spokesperson confirmed that following expert advice, the two chemicals have now been separated and are being safely stored in sheltered locations. No adverse effects have been reported by anyone nearby at the time.
Specialists from the company Wastage are carrying out a clean-up operation, with support from the Environmental Agency. Whilst underway, the area remains closed to the public.
The spokesperson said the incident is a reminder of the importance of proper risk assessment and handling of reactive chemicals during importation, storage, and disposal.
According to the Government, while Brexit has made dealing with some waste streams harder the disruption to waste chemicals has been minimal so far.
The company Wastage is expected to export the chemicals to a licenced facility outside of Gibraltar.
And the Environmental Safety Group calls for an urgent review on all similar local businesses so that basic but dangerous mistakes are not repeated in future.
The group says it's relieved no injuries have been reported and commends the agencies involved as first responders dealing with an unexpected and alarming situation.
It says it expects that responsibility for this incident will be laid on the company concerned.
