Team from Vidya Bhawan polytechnic carried out a technical investigation into the tragic incident at S L Chittora’s house that took 4 lives due to suffocation while cleaning a septic tank last night.

After the survey, the team cited improper construction, maintenance and non-scientific way of cleaning the tank as the reasons behind the incident. The team was led by Principal Dr Anil Mehta and included Bherulal Prajapat, Sudhir Kumawat, Shiv Prakash Kurmi, Manish Sharma and Mahendra Pal Singh.

Mehta said that the tank was constructed around 25-30 years back and as per the information received, it was cleaned only once during the entire period. Septic tank had three sections with each section being 3 feet long, 4 feet wide and 7.5 feet deep. The first section was for solid waste, second for solid and liquid combined and third one was for water release and outlet. There was no provision of a free board above the sections.

Mehta said that septic tank needed to be cleaned every 3-5 years but as per information received was being cleaned once every 10-15 years. Further, due to improper construction, there were leakages along the border of the septic tank. Resultantly the septic tank sewage was not getting reated properly and resultantly the chamber carried poisonous gas.

It was further cited that to soften the sludge that had deposited at the base of septic tank, salt was used by the cleaning staff. This acted as a catalyst in chemical reaction and expedited release of poisonous gas.

All deaths happened in third chamber. The connection between second and third chamber was also found to be faulty and this had led to complete isolation of oxygen from the third chamber and conversion to hydrogen sulfide. As a result, within 3-5 minutes of people entering the chamber, their body got devoid of oxygen and this resulted in their deaths.

Recommendations to Readers:

• Septic tanks should be made as per guidelines. Provision for free board should be made and inlets and outlets should also be properly made.
• Hydrochloric acid should not be used in toilets
• Tank should be cleaned every 3-5 years
• Tank should be cleaned only during day time.
• Tank should be first tested with gas detected before cleaning and cleaning should be done wearing oxygen mask, gum boots and gloves.