Chemical release incidents
Some events particularly stress the emergency medical services system and require executing disaster protocols and plans. This paper compares the impact of two chemical release incidents (CRI) in Richmond, California on Emergency Department (ED) utilization, population health, and community burden in 2007 and 2012.
About 5:30 PM on Monday, 06-Aug-2012, as workers attempted to repair a hydrocarbon leak, a major fire erupted at the Chevron Refinery (Refinery) in Richmond. The Refinery is located in western Contra Costa County (County) on the shores of San Francisco Bay. Five emergency responders had minor burns and received first aid . Refinery CRI can result in fires, as here, or be a consequence of fires or other disasters.
As it had done after previous CRI at this Refinery, the County activated a Level 3 Community Warning System notification for Richmond, North Richmond, and San Pablo, with phone calls and sirens warning people to go indoors and shelter-in-place (SIP) . Residents of warned communities live within 4–5 miles of the Refinery. Some calls notifying residents to SIP did not occur until over 4 hours after the release . The County initiated the Multi-Casualty Incident Plan at “Tier 0”, denoting a major incident with no reported casualties, with alerts to hospitals, ambulance services, and other key health service personnel.
Nearby EDs were quickly overwhelmed and put on ambulance diversion. The 911 system also was overwhelmed, with ambulances responding to nearby communities and with EDs outside the immediate area experiencing surges. Due to the large number of patients seeking emergency care and calling ambulances, the County upgraded the Multi-Casualty Incident Plan to Tier 3, incident with mass casualties or potential for mass casualties . Most people did not require inpatient care. However, the number of patients seeking treatment continued to surge for weeks.
The Refinery has a history of less serious CRI requiring SIP warnings: Monday 12-Apr-1989 , Thursday 25-Mar-1999, Thursday 31-Jan-2002, Wednesday 16-Sep-2003, and Monday 15-Jan-2007 . This study focuses on the 2007 and 2012 CRI.
The County is home to other major refineries with their CRI histories before and after 2012 . Two are in nearby Rodeo and two are to the immediate east of Rodeo in Martinez along the County northwest shore, in turn about 10 and 20 miles from the subject Refinery. One Rodeo refinery paid nearly a million dollars in fines since 2014  and currently is seeking permits to become a major tar sands processor [6, 7]. These refineries and all towns affected by the 2012 CRI are 0–10 miles from the Hayward Fault upwelling [8, 9]. Earthquakes along the San Andreas Fault to the west and the Hayward Fault formed San Francisco Bay.
Health impact of chemical release incidents
Human health can be affected by exposure to various types of particle pollution from major industrial or natural CRI as well as by chronic exposure to power plant by-products [10, 11]. Events such as Seveso, Three Mile Island, Bhopal, Chernobyl, World Trade Center, and Fukushima  are examples of major CRI. Earthquakes [13,14,15], train wrecks [16, 17], hurricanes [18, 19], and wildfires [20, 21] also include CRI. Environmental contextual factors such as the nature of the incident (natural, technological, unintended, or deliberate), duration, setting, and size influence the ability of responders to care for victims . A systematic review of seven decades of disaster management literature found that less than 1 in 5 of 9433 articles used a quantitative methodology to understand these events and concluded that an evidence-informed approach to disaster management is needed .
Smoke from chemical releases and fires contains various carcinogens and un-combusted hydrocarbons with particulate matter (PM) of various sizes. The most dangerous, called “ultrafine”, are less than 2.5 uM (micrometer). This PM size can deposit in the trachea and bronchial tree and can be inhaled as deeply as the alveoli .
The first acute effects of inhalation are irritation to the eyes, nose, and throat. Toxicities are principally respiratory, for example, acute asthma in children [25, 26]. Respiratory effects are rapid and occur with only a one-hour exposure , with the lungs usually bearing the most serious impact. The cardiovascular system is also involved, either secondary to pulmonary damage or directly . For example, during the brief time cleaning up after a fire without breathing protection, firefighters have a significant decrease in pulmonary function with evidence of increased alveolar capillary membrane permeability .
Smoke inhalation produces long term pathology that includes worsening of asthma and cardiovascular effects such as stroke and cardiac disease [21, 30, 31]. People with existing heart or lung disease, people with diabetes, older adults, children, and people of lower socio-economic status have greater risk of particle pollution health effects [8, 9, 32].
Chronically exposed to PM from various refineries ringing its shores and crosshatched with several highly-trafficked freeways, County residents of all age groups have higher rates of asthma-related ED visits, hospitalizations, and deaths as compared to Californians state-wide , with west County residents having extremely high rates . The west County region has six times more diesel air pollution per square mile annually (more than 5 tons) than the County as a whole (0.8 tons), and 40 times more than California state-wide (0.1 ton) .
Importance of adequate air monitoring
In a large industrial fire, smoke and its associated chemicals may affect residents in both nearby and upwind or downwind neighborhoods. Unfortunately, no air monitoring was done for the 2007 event, and no reliable air quality data exists for the 2012 event. Monitoring stations were not located near affected neighborhoods, and monitoring did not begin until after emergency responders extinguished the fire .
Fence-line, community, and mobile monitoring are standard air monitoring methods, and each serves a distinct purpose. Fence-line monitoring primarily identifies non-routine emissions during normal operation . Community monitoring provides data to develop spatial gradients of chronic exposure . Mobile monitoring supplements on-going monitoring during incidents . Time resolution for each method will differ, with fence-line on the order of hours, and mobile only under special circumstances.
The first monitoring after the 2012 fire was by the Bay Area Air Quality Management District’s (BAAQMD) permanent monitors, which would be classed as community monitors. Of the 40-monitor network, only five were in the western County where all refineries are located. BAAQMD monitors sample for hydrogen sulphide, elemental carbon, ozone, sulfur dioxide, and PM 10. The only reliable PM monitor, 2 miles east of the Refinery, did not sample until after the fire ended. About 2 hours after the fire ended, BAAQMD also used ambient air canisters at eight individual locations, analysing 23 compounds including benzene, toluene, and ethanol. Again, no BAAQMD monitoring assessed PM or un-combusted hydrocarbons.
The evening of the 2012 CRI, the Refinery took 17 direct-reading samples for hydrogen sulphide, sulfur dioxide, and carbon monoxide in Richmond, and collected 19 Tedlar bag samples in downwind communities to test for hydrocarbon and sulfur compounds. Over the next 2 days, the Refinery did more follow-up monitoring for hydrogen sulphide, sulfur dioxide, and carbon monoxide. However, as here, refinery fires typically are relatively short events, and sampling after the event is not helpful to show community impacts. No sampling tested for heavier hydrocarbons that could indicate the severity of pollution from a refinery fire.
If available, two other methods can measure exposure: analysis of photos of the event and meteorological analysis. Available photos show fire and smoke from four distinct locations within the Refinery boundaries, with thick, black particulate matter spreading across a large geographic area and into the atmosphere. Exact times and locations for photos were not standard, and the fire burned well past sunset. Thus, it was not possible to conclude anything but that dense black smoke was consistent with PM presence. Meteorological analysis was inconsistent because of placement of weather stations, two on a pier about 2 km southwest of the fire separated by a 300 m high ridge, and another about 2 km northeast of the fire. Such facilities may experience very different wind patterns .