Evidence is emerging that the Ghana Water Company Limited (GWCL) may have used expired chemicals to purify water that reaches consumers' taps.Joy News has learnt that National Security officials are taking the allegation, first reported in the New Crusading Guide newspaper, very seriously and have dispatched BNI operatives to the Weija water treatment plant to conduct further investigations.The aluminium sulphate, or alum, imported from China by the Ghana Urban Water Company to purify tap water, expired last June, raising serious public health questions.Public Affairs Director of the Ghana Standards Authority (GSA) Kofi Amponsah Bediako told Joy FM’s Top Story that his organization would take samples of the chemical and test it to ascertain “how long it has expired and the efficacy level.”“The danger is that its efficiency will go down,” he explained.He said if they are able to establish that the chemical represents a threat, the water company would be asked to stop using it.However, Mr Amponsah Bediako absolved GSA of any blame, saying it makes economic sense for the company to import large quantities of the chemical and maintaining that the GSA cannot be held responsible if the product expired because it was not used within the required time.Ben Arthur, Executive Secretary of the Coalition of NGOs in Water and Sanitation, said the issue is a critical one for Ghanaians, especially those who drink tap water.He recommended that an independent investigation be conducted into the matter to clarify the quality of water being distributed by GWCL. He also asked why a company would want to use expired chemicals to treat water for human consumption.The primary concern is whether the expired chemical was actually used in purifying water for consumers and if so, on what scale.Meanwhile, GWCL Public Affairs Director Stanley Martey told Joy News that the company has not used the expired chemical in question.He assured the public that the water being distributed by the GWCL is wholesome and of the “best quality.”