Pretoria - An underground gas leakage was responsible for the explosion at Telkom's Yeoville building, says the telecommunication company.
"An underground gas leakage in the Yeoville, Johannesburg area was responsible for this morning's (Wednesday) explosion which damaged Telkom's exchange as well as adjacent buildings," said Telkom in a statement.
The explosion, which occurred yesterday morning, resulted in two people being injured. One of the injured, who was a Telkom technician, was hospitalised and is in a stable condition in hospital.
It was earlier believed that a municipal transformer at Telkom's exchange in Yeoville had exploded.
The explosion affected voice, data, DSL and MCO (mobile cellular operator) links with the company citing service restoration as its highest priority.
Telkom, however, added that progress to do this was being delayed because the building which houses Telkom's exchange was declared unsafe by the Johannesburg Fire Department.
"Telkom is continuing investigations into the matter and is determining the most appropriate course of action to expedite service restoration," said company spokesperson Ajith Bridgraj.