(CNN) -- The National Transportation Safety Board on Friday released the first report on the natural gas pipeline explosion that killed eight people in San Bruno, California, last year.
A short time after the blast, NTSB investigators spent more than a week at a facility in Ashburn, Virginia, examining three pieces of the 30-inch-diameter steel pipe from the explosion, according to the report on the agency's website.
The Metallurgical Group report includes detailed facts and pictures of the condition of the ruptured pipe, a statement said, but does not include any analysis of those facts.
The September 9 blast sent a 28-foot section of the gas pipeline 100 feet into the air and blew in the doors of a grocery store a quarter-mile away.
The explosion and fire injured 52 people and destroyed 37 homes.
The government report is the first in a series of factual reports the NTSB is developing during the investigation, the agency said. Additional reports will be released on the first day of the fact-finding investigative hearing that the NTSB will hold in Washington, D.C., on March 1-3, according to the agency statement.
Those reports will focus on operations, human performance, survival factors, the scene of the fire and meteorology.
A determination of a cause isn't expected to be released until the final report is complete.