WISCONSIN ELECTRIC - GAS OPERATIONS, D/B/A WE ENERGIES — Gas distribution — incident on 2008-04-02

Gas distribution incident in CITY OF OCONOMOWOC, WAUKESHA County, WI. Reported cause: 9. Reported consequences: 0 fatalities, 1 injuries, $2,088 reported property damage. Operator-reported incident data submitted to PHMSA, generally within 30 days. Records may be supplemented or corrected and do not represent final agency causal findings.

Report number: 20080078.

Operator ID: 22763.

Reported incident date: 4/2/2008.

Cause detail: THIRD PARTY EXCAVATION DAMAGE

Cause detail: ON WEDNESDAY, APRIL 2, 2008 AT 12:22 P.M., A CONTRACTOR INSTALLING CATCH BASINS AND ASSOCIATED LATERALS IN THE INTERSECTION OF WISCONSIN AVENUE AND WORTHINGTON STREET IN THE CITY OF OCONOMOWOC, WISCONSIN, CALLED WE ENERGIES GAS EMERGENCY RESPONSE NUMBER. THE CONTRACTOR STATED HE HAD PUSHED DOWN ON AN OLD PIPE BECAUSE IT WAS GETTING IN THE WAY OF THEIR CONSTRUCTION WHEN HE HEARD A HIZZING NOISE AND SMELLED GAS. GAS DISPATCH CATEGORIZED THE LEAK AS A GRADE 1 (GRADE 1 IS DEFINED AS A POTENTIALLY HAZARDOUS LEAK) AND SENT THE FIRST RESPONDER TO THE SITE. THE FIRST RESPONDER ARRIVED AT THE SITE AT 12:39 P.M. AND INSPECTED THE EXCAVATED AREA INDICATED BY THE CONTRACTOR. HE OBSERVED AN EXPOSED 2" GAS LINE IN THE DITCH AND ANOTHER UNKNOWN BENT BLACK PIPE NEAR A NEWLY INSTALLED CATCH BASIN. HE FOUND NO INDICATIONS OF THE SOURCE OF THE GAS LEAK IN THE EXCAVATION, ALTHOUGH HE WAS READING THE PRESENCE OF GAS ON HIS INSTRUMENT. HE PROCEEDED TO CHECK THE SURROUNDING AREA INCLUDING THE AREA ALONG THE WALL OF THE NEARBY CHURCH. HIS READINGS INDICATING THE PRESENCE OF GAS REMAINED THE HIGHEST IN THE EXCAVATED AREA. AT 12:44 P.M. HE RETURNED TO HIS VEHICLE TO CALL FOR ADDITIONAL ASSISTANCE ON HIS VEHICLE RADIO. WITHIN MINUTES, ADDITIONAL UNITS ARRIVED TO ASSIST WITH THE LEAK LOCATING EFFORT. THE AREA AROUND THE CHURCH WAS CHECKED AGAIN, BUT INDICATIONS POINTED TO THE EXCAVATED AREA AS A POTENTIAL LEAK SOURCE. HAND EXCAVATION AND EXAMINATION BEGAN AROUND THE TWO PIPES IN THE OPEN EXCAVATION TO CHECK FOR LEAKS. NONE WERE FOUND. WITH CONTINUED PROBING INDICATING THE PRESENCE OF GAS AND POSITIVE INSTRUMENT READINGS, THE ONSITE PERSONNEL PROCEEDED TO DO THE FOLLOWING: CHECK ADJACENT BUILDINGS INCLUDING THE CHURCH AGAIN FOR THE PRESENCE OF GAS AND OCCUPANTS, PREPARE FOR AN AREA SHUT DOWN OF GAS SUPPLY ACCORDING TO THE EMERGENCY PLAN DEVELOPED FOR THE ROAD RECONSTRUCTION PROJECT AND, CONTINUE SEARCHING FOR THE SOURCE OF THE GAS LEAK. AROUND 1 P.M., THE TECHNICIAN INVOLVED WITH THE PROJECT WAS CONTACTED REGARDING THE LEAK INVESTIGATION. RESEARCH REVEALED THAT THE EXPOSED SECTION OF 2" BLACK PIPE WAS POSSIBLY ASSOCIATED WITH THE RETIREMENT AND REPLACEMENT OF A FORMER 2" LINE IN 1968. FURTHER REVIEW INDICATED THAT A SHORT SEGMENT (STUB) OF PIPE CONTAINING A COMPRESSION COUPLING, THOUGHT TO HAVE BEEN RETIRED, MAY STILL BE ACTIVE UNDER THE PAVEMENT TO THE NORTH OF THE EXCAVATION. GIVEN THAT INFORMATION AND LOCATION, THE SEARCH EFFORT WAS DIRECTED TO VERIFYING THE STATUS OF THE LINE AND LOCATING THE COUPLING. PROBING INTHE CONCRETE PAVEMENT BEGAN AT THE LOCATION GIVEN AND THE SECOND PROBE TAKEN RESULTED IN A BLOW OUT OF SAND AND GRAVEL MATERIAL INDICATING THE THEY WERE NEAR THE SOURCE OF THE LEAK. GIVEN THE KNOWLEDGE THAT THE SOURCE OF THE LEAK WAS UNDER UNEXCAVATED SOIL AND PAVEMENT AND NOT KNOWING THE EXTENT OF THE LEAK AREA, THE FOLLOWING ACTIONS WERE TAKEM: THE GAS DISPATCH CENTER WAS ASKED AT 1:16 P.M. TO REQUEST ASSISTANCE FROM THE FIRE & POLICE DEPARTMENTS TO CLOSE OFF THE STREETS TO THE AREA AND GAIN ACCESS TO THE UNOCCUPIED CHURCH. THE PROCESS OF VALVING OFF THE AREA BEGAN AND THE IMMEDIATE AREA WAS CLEARED OF UNNECESSARY PERSONNEL. BY THIS TIME, WE ENERGIES HAD A TOTAL OF 6 PEOPLE IN THE AREA. AT APPROXIMATELY 1:20 P.M., NATURAL GAS THAT HAD ACCUMULATED IN THE LOCKED NEARBY CHURCH, WAS IGNITED BY AN UNKNOWN SOURCE, EXPLODED AND DESTROYED THE CHURCH. ANOTHER BUILDING BEHIND THE CHURCH WAS ALSO DESTROYED BY THE SUBSEQUENT FIRE. SEVERAL OTHER BUILDINGS IN THE AREA ALSO SUFFERED DAMAGE DUE TO THE EXPLOSION AND SUBSEQUENT FIRE. THE FORCE OF THE EXPLOSION PUSHED ONE OF THE GAS EMPLOYEES AGAINST A NEARBY MOBILE COMPRESSOR INJURING HIM AND REQUIRING SEVERAL DAYS OF HOSPITALIZATION. TWO OTHER EMPLOYEES WERE EXAMINED THE FOLLOWING DAY BY THE WE ENERGIES NURSE AND A CLINIC AND WERE GIVEN LIGHT DUTY ASSIGNMENTS DUE TO STRAINS AND OTHER MINOR INJURIES. A TOTAL OF THREE COMPANY EMPLOYEES WERE INJURED IN THE EXPLOSION AND AN INDIVIDUAL WHO WAS IN O NE OF THE NEARBY HOMES WAS BELIEVED TO HAVE BEEN MEDICALLY EXAMINED. NEWS REPORTS INDICATED THAT SOME EMERGENCY PERSONNEL MAY HAVE BEEN TREATED FOR SMOKE INHALATION. POST INCIDENT REVIEWS, INTERVIEWS AND FURTHER EXCAVATION AND EXAMINATION OF THE BURIED PIPE INDICATE THE CONTRACTOR UNCOVERED A 2" PIPE STUB THAT WAS CONNECTED TO THE GAS DISTRIBUTION SYSTEM. THEY ASSUMED IT TO BE ABANDONED AND PUSHED DOWN ON IT WITH THE BUCKET OF THE BACKHOE TO MAKE ROOM FOR A NEW STORM SEWER. THE SIGNIFICANT DISTORTION TO THE PIPE CAUSED IT TO SEPARATE FROM A BURIED UPSTREAM INSULATED COMPRESSION STYLE COUPLING. THE PATHWAY OF THE RELEASED GAS TO AND INTO THE CHURCH IS NOT KNOWN BECAUSE THE SEPARATION OCCURRED UNDER PAVEMENT AND IN SOILS STILL FROZEN FROM WINTER CONDITIONS. ALL SIX OF THE WE ENERGIES EMPLOYEES ON SITE AT THE TIME OF THE INCIDENT UNDERWENT DRUG AND ALCOHOL TESTING AND THE RESULTS WERE NEGATIVE FOR ALL SIX.

PHMSA trend classification: significant incident, serious incident, not fire-first.

PHMSA standardized cause: EXCAVATION DAMAGE — THIRD PARTY EXCAVATION DAMAGE.

PHMSA indexed costs: $2,088 reported total cost, $898.431 in 1984 dollars, $1,103.137 in current-year dollars.

PHMSA trend flags, standardized causes, and indexed costs are analytical fields added to operator-reported incident data. They do not represent final agency causal findings.