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Acute Health Effects Due to a Large Sulfuric Acid Release in Richmond, California. Phase II Report
Written: 03/01/98


            The release described in the report occurred at approximately 7:15 AM on the morning of July 26, 1993, during the unloading of a railroad tank car on the General Chemical premises in Richmond, and lasted about four hours.  The resulting cloud of sulfuric acid extended several miles over residential communities of Richmond and San Pablo.  Thousands of persons per day sought medical attention at local clinics and emergency rooms for several days after the release.  Newspaper accounts put the final total affected at more than 20,000 persons. 


         The California Department of Health Services obtained funding from the federal Agency for Toxic Substances and Disease Registry to investigate the public health impacts of the release.  The goals of the investigation were to review hospital records of persons who sought care at local emergency departments as a result of the spill, and to interview a sample of these individuals to get additional information.  The main study questions were:

  What health effects were reported among those seeking medical care?

  What distinguished people with severe symptoms from those with milder symptoms?

  At what estimated exposure levels did health effects occur?

  How did people who sought medical care learn of the release?


         Our efforts were conducted in two phases.  In the first phase, we reviewed patient records of four medical facilities closest to the release (Brookside Hospital, Kaiser Richmond, Richmond Health Center, and Martin Luther King Jr. Family Health Center), and identified over 14,000 release-related records from these facilities during the first week after the incident.  Findings from this phase are summarized in the attached report, but a separate complete report of Phase One activities is also available. 


         In the second phase, described in detail in the attached report, we conducted follow-up interviews by telephone with a random sample of about 400 people identified in Phase One to get more information about them, such as their whereabouts the morning of the release, and what health effects they experienced beyond what was available in their medical records.  Because no measurements of sulfuric acid in the air downwind were taken during the release, we had to rely on computer simulations of the acid plume prepared by scientists at Lawrence Livermore National Laboratory to estimate the levels of sulfuric acid people may have been exposed to. 


What Health Effects Were Reported?


         We found and reviewed over 14,000 medical records from spill-related visits to the four facilities the first five days after the spill.  The majority of persons who sought care at these emergency departments reported respiratory signs and symptoms (such as coughing and shortness of breath), nausea, vomiting, irritated eyes, headaches, and skin irritation.  They spanned all ages and ethnic groups in the area.  About 5% had experienced health problems that could be seen or heard by a health care professional during a physical examination, such as wheezing or other abnormal breath sounds, or vomiting.  For the purposes of this study, we called these observable health problems “target symptoms.”  In the remaining 95% of visits, persons reported either 1.) symptoms which could not be seen or otherwise documented during a physical examination, such as headache or itchy eyes (we called these “non-target” symptoms), or 2.) no health problems at the time of the examination. 


What Distinguished Those with More Severe Symptoms?


         The exposure clearly affected a broad cross-section of the population.  Nevertheless, we identified a few characteristics that distinguished the people with target symptoms, whom we assumed were more severely affected than those without target symptoms.  Based on our interviews with 400 persons (some with target symptoms and some without), persons with target symptoms tended to be older than those with non-target symptoms, and were somewhat more likely to report that their health effects lasted more than a week after the release.  Smokers were more likely than non-smokers to have had respiratory effects in particular.  Persons relating a history of asthma prior to the release had more than three times the likelihood of having target symptoms. 


At What Exposure Levels Were Health Effects Seen?


         Symptoms were reported by people across all the estimated exposure levels.  Using the computer model of the release, we estimated that while no one had life-threatening exposures, about half of the people we interviewed had levels of exposure that have been reported in the medical literature as causing respiratory irritation and coughing.  However, about one-third of those surveyed, even those with target symptoms, were outside the lowest exposure areas predicted by the computer model. 


How Did People Learn of the Release?


         The largest group of people in this study (about 40%) said they first learned of the release through word of mouth, talking to friends or relatives, either in person or by phone.  Another third heard through radio or television.  More than one-third were away from home at the time of the 7:15 AM release. 


         About half of the study group said they did not learn of the shelter-in-place advisory during the release, or were not in a position to take shelter.  Of those who did hear of the advisory, most said they were able to take appropriate protective action. 




         This incident created a tremendous response from the communities.  The equivalent of about 10 to 12% of the population of Richmond and San Pablo sought medical care at just these four health facilities, creating a dramatic overload of the health care systems. 


         A release of this type, as we have seen in hazardous materials releases in other communities as well, seems to provoke symptom responses in many more persons than the estimated exposure levels might predict.  This could be because the general population includes many people who are more susceptible to the irritating effects of chemicals, or that the stress of a community-wide emergency drives people to seek health care who might otherwise have stayed at home, or that expert opinion about how irritating certain exposures are is wrong.  The elderly, and those with pre-existing conditions such as asthmatics and smokers, may be the most susceptible.  In any case, we can expect a profound and far-reaching public response to community-wide hazardous materials releases such as this. 


         Finally, we must assume that at most times of the day, a large proportion of the population will be away from home, and possibly separated from normal sources of information, such as telephone, television, and radio.  Consequently, for these people other sources of warning information, such as a siren system, coupled with a broad-based education campaign, may be important. 




·         It is of paramount importance to prevent chemical accidents from occurring in the first place. 

·         The warning system for residents needs to be improved in the event an accident does occur:

—Special efforts should be made to warn and provide treatment to individuals who are elderly or have chronic respiratory conditions.

—Strategies should be developed to provide shelter-in-place advisories for people who are not at home.

—Notification should be improved for Laotian and other Southeast Asian communities

·         Exposure measurements should be taken whenever possible during similar events. 

·         Record-keeping at health care facilities should be improved and standardized regarding exposure and health effects in persons seeking care in emergencies.