West Fertilizer Plant Explosion A Disaster Epidemiology Study Hammad Akram MD MPH Epidemiologist Waco McLennan County Public Health District
West, Texas (McLennan Co) Population (2012): 2831 Area: 1.64 mi 2
Residential Area Nursing Home Middle School Apartment Complex Aerial photo of fertilizer plant before blast Plant area Source: Dallas Morning News with editions/labels
Timeline of Fertilizer Plant Explosion April 17, 2013 7:29 pm Fire reported at West Fertilizer Plant 7:32 pm West Volunteer Fire Department dispatched 7:38 pm West volunteer fire fighters arrive on scene 7:41 pm Request for mutual aid from Hill County departments and other local departments 7:51 pm Explosion occurs
Source: Dallas Morning News
Magnitude of Explosion 28 34 tons of ammonium nitrate exploded (another 120 tons did not explode) Registered as 2.1 magnitude earthquake Felt over 30 miles away Blast crater approx 10 feet deep and 100 feet wide Flaming debris causes fires over a half mile Furthest piece of debris found 2.5 miles away Photo of blast site with bent railroad tracks Source: Associated Press
Half of Homes in West were Impacted 142 destroyed 51 major damage 27 minor damage 130 otherwise affected
Apartment complex destroyed Aerial photo of destroyed apartment building Source: Associated Press
Nursing Home Evacuation Nursing home located 200 yards from fertilizer plant Emergency plan to shelter in place was executed after fire started 127 residents ultimately evacuated to local and regional care facilities Google Maps photo of destroyed nursing home
Epidemiology Response 4/18 Region 7 communicates with Central Office re developing response Late April WMCPHD discusses with Region 7/Central Office regarding CASPER survey June WMCPHD decides to conduct injury epidemiology investigation reaches out to Region 7/Central Office for assistance June Investigation team consults with experts from Oklahoma, CDC July Team plans investigation August Team receives approval from DSHS Institutional Review Board to conduct investigation
Epidemiology Response (continued) September December: Medical Records Abstraction at medical facilities in Waco, Hillsboro, Temple, Dallas, Fort Worth October: Data Collection from Dallas County Medical Examiner s Office December February: Conduct Survivor Interviews November now: Ongoing Data Analysis
Epidemiology Response: Collaboration among Governmental Partners Local Waco/McLennan County Public Health District 2 epidemiologists, 1 preparedness coordinator, 1 public health nurse, 1 preparedness planner Regional Texas Department of State Health Service Region 7 1 epidemiologist, 1 public health nurse State Texas Department of State Health Services 2 epidemiologists, 1 health geographer Federal CDC Epidemic Intelligence Service 1 epidemiologist
Objectives of Investigation 1. To describe the characteristics of fatal injuries caused by the explosion 2. To describe the physical injuries of survivors of the explosion 3. To describe risk factors associated with injuries caused by the explosion, including location at the time of the blast, timing of injury, and demographic characteristics. 4. To quantify the number of acutely injured persons who sought medical care 5. To describe the medical care received by the injured
Case Finding 1. Fatal injuries = persons who died in McLennan County as result of injuries sustained in blast within one week 2. Non fatal injuries = persons who sought medical treatment for injuries related to the explosion, identified through medical records: a. Injury treated at any hospital, emergency room, or urgent care facility in McLennan or Hill County within 5 days with cause and timing of injury consistent with being related to the blast. b. Injury treated at a Texas hospital known to have received injured patients within one month and identified by that hospital as being related to the blast.
Multi pronged Approach to Identify the Injured and Collect Data Timeliness of identification Immediate Long term Type of Injury Fatal Death certificates Medical Examiner s reports Non fatal Hospital patient lists Mobile Medical Unit list Medical records abstraction Survivor interviews Additional data sources: West Rest Haven (nursing home) census list Federal Emergency Management Agency (FEMA) list of applicants for assistance
Medical Record Abstraction Mode of arrival at the treatment facility Mechanism of injuries Types of injuries Medical resources used by patients Disposition: treated and released, admitted and/or transferred etc. Descriptive information
Survivor Interviews Patients who sought medical care were contacted by telephone Contact information obtained from medical records, FEMA Exclusions Children ( 18 years) Residents of nursing home If unreachable by phone, survey was mailed
Survivor Interviews Location at the time of explosion Timing of injuries To identify any injuries that were missed in the medical records Other information : demographics, how survivors received situation updates, trapped or not, structural & property damage around the survivors etc.
Person Persons who died in McLennan County as result of injuries sustained in blast within one week Persons who sought medical treatment for injuries related to the explosion, identified through medical records Their demographic characteristics
Place At the time of explosion/injuries sustained: Inside a structure Outside Outside in a car
Time Time of injuries During the explosion After the explosion (for example, during clean up) Time of arrival at the health care facilities
Future Analyses: Distance from Blast Persons directly injured by blast have been geocoded (From medical records & survivor interviews ) Determine relationship of distance from blast on types of injuries Create injury density maps
Challenges Communication of the case definitions to data sources Intense media interest
Promising Best Practices Existing epidemiology capacity at local, region, state levels Consultation with blast and disaster experts 1995 OKC bombing (Oklahoma State Dept of Health) 2011 Alabama tornado (CDC) Established working relationships with hospitals and urgent care facilities PTSD training/awareness provided to medical abstraction and interview teams Access to FEMA data Use GIS in injury mapping
Epidemiology Investigation Team Waco McLennan County Public Health District Hammad Akram Stephanie Alvey Alicia Hernandez Debbi Parker Kahler Stone Texas DSHS Region 7 Carol Davis Bonnie Feldt Sandi Henley Sharon Melville Texas DSHS Central Office Tracy Haywood Kristi Metzger Duke Ruktanonchai David Zane
Acknowledgements To federal and state agencies, hospitals, urgent care facilities, medical examiner, justice of the peace, RACs, regional and local health departments, and other organizations To local officials, residents, fire fighters, and others affected by the explosion who, despite enormous grief and displacement, graciously contributed information for this investigation
Thank you! Hammad Akram Epidemiologist Waco McLennan County Public Health District 254 750 5450 hammada@ci.waco.tx.us