​About 3:55 PM, December 6, 1985, a natural gas explosion and fire destroyed the River Restaurant at 268 Main Street in Derby, CT. Gas escaping from a broken gas main at a pressure of about one pound per square inch had escaped, migrated into the restaurant basement, ignited, exploded and burned. Of te 19 person inside the restaurant at the time, 6 were killed and 12 were injured; 1 passerby and 1 firefighter were also injured. 

After the accideent the street adjacent to the restaurant was excavated to where a 24 inch diameter sewer system had just been installed, an 87 year old, 3 inch diameter, cast iron natural gas main was found to be broken. 

​We determined that the probable cause of the explosion and fire in the restaurant was the improper planning, execution and supervision of constuction activities on the parts of the construction company and the gas company which resulted in the undetected fracture of the 87 year old, 3 inch diameter, cast iron gas main. 

​​​​​​As a result of this investigation, we made​ the following safety recommendations:​​

To National Utility Contractors' Association: Notify its member compnaies of the circumstances of this accident and urge them to be sure, when conducting excavation operations near buried gas lines, that their construction crews are alerted to the existance and promimity of the gas lines. (P-86-16)

To the American Gas Association and the American Public Gas Association: Develop, in conjunction with the American Society of Mechanical Engineers, Gas Piping Standards Committee, specific guidelines for the replacement of cast iron gas mains in large, medium, and small gas distribution companies. The guidelines should include, but not be limited to such factors as pipe age, ipe age, pipe diameter, soil corrosivity, buried depth, and external loading. (P-86-17)

To the City of Derby, Connecticut: Establish in contracts that involvve excavation activities specific authority and responsiblity for detecting and correcting any unsafe activities and specifically provide for stopping all excavation-related work until the unsafe conditions are corrected. (P-86-18)

To the Northeast Utilities Service Company:

• Emphasize in its training of operating personnel the importance of following the company procedures for patrolling and protecting its gas mains in proximity to excavation projects. (P-86-19)
  
• Consider the abandonment of cast iron gas mains prior to any excavation work in their proximity. Where abandonment is not proactical or feasible prior to the excavation work, assign inspectors to the job site to monitor the excacation work. (P-86-20​)