ADVANCED DIAGNOSTIC IMAGING AND PATHOLOGIC FINDINGS OF THYROID LESIONS IN TWO SHORT-BEAKED ECHIDNAS (TACHYGLOSSUS ACULEATUS).

Two zoo-maintained short-beaked echidnas (Tachyglossus aculeatus) had long histories of intermittent anorexia and lethargy. Case 1 presented with a recurrence of these signs after transfer to another facility and died shortly after arrival. A focal area of hyperattenuation within the paratracheal tissue of the cranial mediastinum was noted antemortem on CT. Postmortem, this corresponded with severe thyroid follicular hyperplasia with lymphoplasmacytic thyroiditis. Additional findings included a systemic fungal infection without an inflammatory response, suggesting underlying factors such as torpor or immunosuppression. In Case 2, an intrathoracic mass was identified during a preshipment examination. CT confirmed a contrast-enhanced mass compressing the cranial vena cava and right atrium, and the animal was euthanized. The mass was diagnosed histologically as thyroid adenocarcinoma. These cases report thyroiditis and thyroid adenocarcinoma in echidna and describe the use of IV contrast and CT as a diagnostic aid in this species.

Ranavirus (Frog Virus 3) Infection in Free-Living Three-Toed Box Turtles (Terrapene mexicana triunguis) in Missouri, USA.

Frog virus 3 (FV3) and related ranaviruses are emerging infectious disease threats to ectothermic vertebrate species globally. Although the impact of these viruses on amphibian health is relatively well studied, less is understood about their effects on reptile health. We report two cases of FV3 infection, 11 mo apart, in three-toed box turtles (Terrapene mexicana triunguis) from a wildlife rehabilitation center. Case 1 had upper respiratory signs upon intake but had no clinical signs at the time of euthanasia 1 mo later. Case 2 presented for vehicular trauma, had ulcerative pharyngitis and glossitis, and died overnight. In case 1, we detected FV3 nucleic acid with qPCR in oral swabs, kidney, liver, spleen, and tongue. In case 2, we detected FV3 in an oral swab, an oral plaque, heart, kidney, lung, liver, spleen, and tongue. We also detected FV3 nucleic acid with in situ hybridization for case 2. For both cases, FV3 was isolated in cell culture and identified with DNA sequencing. Histopathologic examination of postmortem tissue from case 1 was unremarkable, whereas acute hemorrhagic pneumonia and splenic necrosis were noted in case 2. The difference in clinical signs between the two cases may have been due to differences in the temporal course of FV3 disease at the time of necropsy. Failure to detect this infection previously in Missouri reptiles may be due to lack of surveillance, although cases may also represent a novel spillover to box turtles in Missouri. Our findings reiterate previous suggestions that the range of FV3 infection may be greater than previously documented and that infection may occur in host species yet to be tested.

The same genotype of Sarcocystis neurona responsible for mass mortality in marine mammals induced a clinical outbreak in raccoons (Procyon lotor) 10 years later.

Here, we report the first known outbreak of clinical protozoal myeloencephalitis in naturally infected raccoons by the parasite Sarcocystis neurona. The North American opossum (Didelphis virginiana) and the South American opossum (Didelphis albiventris) are its known definitive hosts. Several other animal species are its intermediate or aberrant hosts. The raccoon (Procyon lotor) is considered the most important intermediate host for S. neurona in the USA. More than 50% of raccoons in the USA have sarcocysts in their muscles, however clinical sarcocystosis in raccoons is rare. In 2014, 38 free-living raccoons were found dead or moribund on the grounds of the Saint Louis Zoo, Missouri, USA. Moribund individuals were weak, lethargic, and mildly ataxic; several with oculo-nasal discharge. Seven raccoons were found dead and 31 were humanely euthanized. Postmortem examinations were conducted on nine raccoons. Neural lesions compatible with acute sarcocystosis were detected in eight raccoons. The predominant lesions were meningoencephalitis and perivascular mononuclear cells. Histologic evidence for the Canine Distemper Virus was found in one raccoon. Schizonts and merozoites were present in the encephalitic lesions of four raccoons. Mature sarcocysts were present within myocytes of five raccoons. In six raccoons, S. neurona schizonts and merozoites were confirmed by immunohistochemical staining with S. neurona-specific polyclonal antibodies. Viable S. neurona was isolated from the brains of two raccoons by bioassay in interferon gamma gene knockout mice and in cell cultures seeded directly with raccoon brain homogenate. Molecular characterization was based on raccoon no. 68. Molecular characterization based on multi-locus typing at five surface antigens (SnSAG1-5-6, SnSAG3 and SnSAG4) and the ITS-1 marker within the ssrRNA locus, using DNA isolated from bradyzoites released from sarcocysts in a naturally infected raccoon (no. 68), confirmed the presence of S. neurona antigen type I, the same genotype that caused a mass mortality event in which 40 southern sea otters stranded dead or dying within a 3 week period in April 2004 with S. neurona-associated disease. An expanded set of genotyping markers was next applied. This study reports the following new genotyping markers at 18S rRNA, 28S rRNA, COX1, ITS-1, RON1, RON2, GAPDH1, ROP20, SAG2, SnSRS21 and TUBA1 markers. The identity of Sarcocystis spp. infecting raccoons is discussed.

Reproductive tract neoplasia in adult female Asian elephants (Elephas maximus).

Recent reports have highlighted a lower-than-expected prevalence of neoplasia in elephants and suggested mechanisms for cancer resistance. But despite infrequent reports in the literature, uterine neoplasia is common in managed Asian elephants (Elephas maximus). This study is an archival review of reproductive tract neoplasia in 80 adult female Asian elephant mortalities in managed care facilities in the United States from 1988 to 2019. Neoplasms occurred in 64/80 (80%) of cases. Most were in the uterus (63/64; 98%) with only a single case of ovarian neoplasia. Myometrial leiomyomas were present in 57/63 (90%) cases with uterine neoplasia. Uterine adenocarcinoma was present in 8/63 (13%) cases. Remaining cases included endometrial adenoma (2), focal carcinoma in situ in endometrial polyps (1), anaplastic carcinoma (1), endometrial hemangioma (1), primitive neuroectodermal tumor (PNET; 1), and angiosarcoma (1). One case with uterine adenocarcinoma had a separate pelvic mass histologically characterized as an anaplastic sarcoma. Distant metastases were documented in 5/8 (63%) cases of uterine adenocarcinoma, and in the uterine anaplastic carcinoma, PNET, and angiosarcoma. Four uterine adenocarcinomas and one carcinoma in situ were examined immunohistochemically for pan-cytokeratin, vimentin, and estrogen receptor. In all, neoplastic cells were pan-cytokeratin positive and vimentin negative, and in 2 cases were immunoreactive for estrogen receptor. Results show that female reproductive tract neoplasia, particularly of the uterus, is common in Asian elephants and is not limited to leiomyomas. Importantly, uterine neoplasms have the potential to impact fecundity and may represent obstacles to conservation in managed care.

Blood stream infections in children in the first year after liver transplantation at Wits Donald Gordon Medical Centre, South Africa.

Children who undergo liver transplantation and subsequently develop BSI are at risk for adverse outcomes. Research from high-income settings contrasts the dearth of information from transplant centers in low- and middle-income countries, such as South Africa. Therefore, this study from Johannesburg aimed to describe the clinical and demographic profile of children undergoing liver transplantation, and determine the incidence and pattern of BSI and associated risk factors for BSI during the first year after liver transplant. Pediatric liver transplants performed from 2005 to 2014 were reviewed. Descriptive analyses summarized donor, recipient, and post-transplant infection characteristics. Association between BSI and sex, cause of liver failure, age, nutritional status, PELD/MELD score, graft type, biliary complications, and acute rejection was determined by Fisher's exact test; and association with length of stay by Cox proportional hazards regression analysis. Survival estimates were determined by the Kaplan-Meier method. Sixty-five children received one transplant and four had repeat transplants, totaling 69 procedures. Twenty-nine BSI occurred in 19/69 (28%) procedures, mostly due to gram-negative organisms, namely Klebsiella species. Risk for BSI was independently associated with biliary atresia (44% BSI in BA compared to 17% in non-BA transplants; P = .014) and post-operative biliary complications (55% BSI in transplants with biliary complications compared to 15% in those without; P = .0013). One-year recipient and graft survival was 78% (CI 67%-86%) and 77% (CI 65%-85%), respectively. In Johannesburg, incident BSI, mostly from gram-negative bacteria, were associated with biliary atresia and post-operative biliary complications in children undergoing liver transplantation.

Needs must: living donor liver transplantation from an HIV-positive mother to her HIV-negative child in Johannesburg, South Africa.

The world's first living donor liver transplant from an HIV-positive mother to her HIV-negative child, performed by our team in Johannesburg, South Africa (SA) in 2017, was necessitated by disease profile and health system challenges. In our country, we have a major shortage of donor organs, which compels us to consider innovative solutions to save lives. Simultaneously, the transition of the HIV pandemic, from a death sentence to a chronic illness with excellent survival on treatment required us to rethink our policies regarding HIV infection and living donor liver transplantation . Although HIV infection in the donor is internationally considered an absolute contraindication for transplant to an HIV-negative recipient, there have been a very small number of unintentional transplants from HIV-positive deceased donors to HIV-negative recipients. These transplant recipients do well on antiretroviral medication and their graft survival is not compromised. We have had a number of HIV-positive parents in our setting express a desire to be living liver donors for their critically ill children. Declining these parents as living donors has become increasingly unjustifiable given the very small deceased donor pool in SA; and because many of these parents are virally suppressed and would otherwise fulfil our eligibility criteria as living donors. This paper discusses the evolution of HIV and transplantation in SA, highlights some of the primary ethical considerations for us when embarking on this case and considers the new ethical issues that have arisen since we undertook this transplant.

Bladder teratoma in a maned wolf (Chrysocyon brachyurus).

Background: Teratomas are germ cell tumors, comprised of a mixture of tissue types and with tissue foreign to their site of origin. Case Description: A 5.5-year-old intact female maned wolf (Chrysocyon brachyurus) was treated for recurrent stranguria and suspected cystitis. Due to lack of resolution, the wolf was anesthetized for further evaluation. The urinary bladder was firm on palpation, with a markedly thickened wall and no observable lumen on ultrasound. Neoplastic infiltration was suspected on double contrast cystogram and confirmed via surgical exploration. The lesion was inoperable and the wolf was euthanized. Gross necropsy revealed two poorly distinguished masses infiltrating the urinary bladder dorsally and caudoventrally, with minimal remaining lumen. Histopathologic examination of the bladder and associated masses revealed a neoplasm comprised of multiple tissue types. Vascular invasion was noted. Conclusion: The neoplasm was diagnosed as an extragonadal teratoma. Few extragonadal teratomas have been described and this is the first report of a teratoma originating in the urinary bladder of a non-human species.

Living donor liver transplant from an HIV-positive mother to her HIV-negative child: opening up new therapeutic options.

OBJECTIVE: Transplant a liver from an HIV-positive mother to her HIV-negative child to save the child's life. DESIGN: A unique case of living donor liver transplantation from an HIV-positive mother to her HIV-negative child in South Africa. Two aspects of this case are ground-breaking. First, it involves living donation by someone who is HIV-positive and second it involves controlled transplant of an organ from an HIV-positive donor into an HIV-negative recipient, with the potential to prevent infection in the recipient. METHODS: Standard surgical procedure for living donor liver transplantation at our centre was followed. HIV-prophylaxis was administered preoperatively. Extensive, ultrasensitive HIV testing, over and above standard diagnostic assays, was undertaken to investigate recipient serostatus and is ongoing. RESULTS: Both mother and child are well, over 1 year posttransplantation. HIV seroconversion in our recipient was detected with serological testing at day 43 posttransplant. However, a decline in HIV antibody titres approaching undetectable levels is now being observed. No plasma, or cell-associated HIV-1 DNA has been detected in the recipient at any time-point since transplant. CONCLUSION: This case potentially opens up a new living liver donor pool which might have clinical relevance in countries where there is a high burden of HIV and a limited number of deceased donor organs or limited access to transplantation. However, our recipient's HIV status is equivocal at present and additional investigation regarding seroconversion events in this unique profile is ongoing.

Sustained reduction in rates of hospital-onset Clostridium difficile infection using an automated electronic health record protocol.

BACKGROUND: An automated protocol was designed within our electronic medical record (EMR) to help curb the Clostridium difficile problem at our institution. The protocol will identify patients at high risk for C difficile, improve the timing of testing of patients infected on admission, and enhance the appropriateness of C difficile testing throughout the patient's hospitalization. METHODS: Admitted patients with 2 of the following 3 criteria were labeled as high risk for C difficile: admission to a medical institution in the preceding 90 days, administration of antibiotics in the preceding 90 days, or a history of C difficile. High-risk patients with diarrhea in the first 3 days of admission are identified in the EMR, and prompt testing for C difficile is done. After day 3, if diarrhea develops, a series of questions is presented to help test the appropriate patients for C difficile. RESULTS: A statistically significant reduction in rates of hospital-onset C difficile was achieved after implementation of the protocol. CONCLUSIONS: Implementation of an automated protocol for targeted testing of high-risk patients for C difficile was successful at reducing rates of hospital-onset C difficile by improving timing and appropriateness of testing.

Medical Response to a Vinyl Chloride Release From a Train Derailment: New Jersey, 2012.

OBJECTIVE: The objective of this investigation was to examine the health impact of and medical response to a mass casualty chemical incident caused by a vinyl chloride release. METHODS: Key staff at area hospitals were interviewed about communication during the response, the number of patients treated and care required, and lessons learned. Clinical information related to the incident and medical history were abstracted from hospital charts. RESULTS: Hospital interviews identified a desire for more thorough and timely incident-specific information and an under-utilization of regionally available resources. Two hundred fifty-six hospital visits (96.2%) were at the facility closest to the site of the derailment. Of 237 initial visits at which the patient was examined by a physician, 231 patients (97.5%) were treated in the emergency department (ED) and 6 patients (2.5%) were admitted; 5 admitted patients (83.3%) had preexisting medical conditions. Thirteen of 14 asymptomatic ED patients were children under the age of 10 years. One hundred forty-five patients (62.8%) discharged from the ED were diagnosed solely with exposure to vinyl chloride. CONCLUSIONS: Continuous emergency response planning might facilitate communication and better distribution of patient surge across hospitals. Individuals with multiple medical conditions and parents and caretakers of children may serve as target groups for risk communication following acute chemical releases. (Disaster Med Public Health Preparedness. 2017;11:538-544).

Hospital Impact After a Chemical Spill That Compromised the Potable Water Supply: West Virginia, January 2014.

In January 2014, a chemical spill of 4-methylcyclohexanemethanol and propylene glycol phenyl ethers contaminated the potable water supply of approximately 300,000 West Virginia residents. To understand the spill's impact on hospital operations, we surveyed representatives from 10 hospitals in the affected area during January 2014. We found that the spill-related loss of potable water affected many aspects of hospital patient care (eg, surgery, endoscopy, hemodialysis, and infection control of Clostridium difficile). Hospital emergency preparedness planning could be enhanced by specifying alternative sources of potable water sufficient for hemodialysis, C. difficile infection control, and hospital processing and cleaning needs (in addition to drinking water). (Disaster Med Public Health Preparedness. 2017;11:621-624).

Acute Health Effects After the Elk River Chemical Spill, West Virginia, January 2014.

OBJECTIVES: On January 9, 2014, approximately 10 000 gallons of a mixture of 4-methylcyclohexanemethanol and propylene glycol phenyl ether spilled into West Virginia's Elk River, contaminating the potable water supply of about 300 000 West Virginia residents. This study sought to describe acute health effects after the chemical spill. METHODS: We conducted a descriptive analysis using 3 complementary data sources: (1) medical records of patients who visited an emergency department during January 9-23, 2014, with illness potentially related to the spill; (2) West Virginia Poison Center caller records coded as "contaminated water" during January 9-23, 2014; and (3) answers to household surveys about health effects from a Community Assessment for Public Health Emergency Response (CASPER) questionnaire administered 3 months after the spill. RESULTS: In the 2 weeks after the spill, 2000 people called the poison center reporting exposure to contaminated water, and 369 people visited emergency departments in the affected area with reports of exposure and symptoms potentially related to the spill. According to CASPER weighted cluster analyses, an estimated 25 623 households (21.7%; 95% confidence interval [CI], 14.4%-28.9%) had ≥1 person with symptoms who felt that they were related to the spill in the 3 months after it. Reported health effects across all 3 data sources included mild skin, respiratory, and gastrointestinal symptoms that resolved with no or minimal treatment. CONCLUSIONS: Medical records, poison center data, and CASPER household surveys were inexact but useful data sources to describe overall community health effects after a large-scale chemical spill. Analyzing multiple data sources could inform epidemiologic investigations of similar events.

CONGENITAL CLEFT PALATE AND CARDIAC SEPTAL DEFECTS IN A NEONATAL SOUTHERN BLACK RHINOCEROS (DICEROS BICORNIS MINOR).

A female Southern black rhinoceros ( Diceros bicornis minor) calf died unexpectedly at less than 12 hr of age, after an uncomplicated birth and uneventful early postpartum period. Gross necropsy revealed a 15-cm full thickness cleft palate, a patent foramen ovale, and four septal defects ranging from 0.3 to 1 cm in diameter. Histologic findings did not reveal any significant abnormalities. Karyotyping did not indicate any significant numerical or structural chromosomal abnormalities.

Toolkit for Epidemiologic Response to an Acute Chemical Release.

When a large chemical incident occurs and people are injured, public health agencies need to be able to provide guidance and respond to questions from the public, the media, and public officials. Because of this urgent need for information to support appropriate public health action, the Agency for Toxic Substances and Disease Registry (ATSDR) of the US Department of Health and Human Services has developed the Assessment of Chemical Exposures (ACE) Toolkit. The ACE Toolkit, available on the ATSDR website, offers materials including surveys, consent forms, databases, and training materials that state and local health personnel can use to rapidly conduct an epidemiologic investigation after a large-scale acute chemical release. All materials are readily adaptable to the many different chemical incident scenarios that may occur and the data needs of the responding agency. An expert ACE team is available to provide technical assistance on site or remotely. (Disaster Med Public Health Preparedness. 2016;10:631-632).

Challenges During a Chlorine Gas Emergency Response.

OBJECTIVE: A chlorine gas release occurred at a poultry processing plant as a result of an accidental mixing of sodium hypochlorite and an acidic antimicrobial treatment. We evaluated the public health and emergency medical services response and developed and disseminated public health recommendations to limit the impact of future incidents. METHODS: We conducted key informant interviews with the state health department; local fire, emergency medical services, and police departments; county emergency management; and representatives from area hospitals to understand the response mechanisms employed for this incident. RESULTS: After being exposed to an estimated 40-pound chlorine gas release, 170 workers were triaged on the scene and sent to 5 area hospitals. Each hospital redistributed staff or called in extra staff (eg, physicians, nurses, and respiratory therapists) in response to the event. Interviews with hospital staff emphasized the need for improved communication with responders at the scene of a chemical incident. CONCLUSIONS: While responding, hospitals handled the patient surge without outside assistance because of effective planning, training, and drilling. The investigation highlighted that greater interagency communication can play an important role in ensuring that chemical incident patients are managed and treated in a timely manner. (Disaster Med Public Health Preparedness. 2016;10:553-556).

MANAGEMENT OF ACUTE RENAL FAILURE WITH DELAYED HYPERCALCEMIA SECONDARY TO SARCOCYSTIS NEURONA-INDUCED MYOSITIS AND RHABDOMYOLYSIS IN A CALIFORNIA SEA LION (ZALOPHUS CALIFORNIANUS).

A 3-yr-old captive-born California sea lion (Zalophus californianus) developed Sarcocystis neurona-induced myositis and rhabdomyolysis that led to acute renal failure. The sea lion was successfully managed with fluid therapy, antiprotozoals, antibiotics, anti-inflammatories, antiemetics, gastroprotectants, and diuretics, but developed severe delayed hypercalcemia, a syndrome identified in humans after traumatic or exertion-induced rhabdomyolysis. Treatment with calcitonin was added to the management, and the individual recovered fully. The case emphasizes that animals with rhabdomyolysis-induced renal failure risk developing delayed hypercalcemia, which may be life threatening, and calcium levels should be closely monitored past the resolution of renal failure.

Exposures and symptoms among workers after an offsite train derailment and vinyl chloride release.

OBJECTIVE: In 2012 in New Jersey, a train derailment resulted in the puncture of a tanker car carrying liquid vinyl chloride under pressure, and a resulting airborne vinyl chloride plume drifted onto the grounds of a nearby refinery. This report details the investigation of exposures and symptoms among refinery workers. DESIGN AND SETTING: The investigation team met with refinery workers to discuss their experience after the derailment and provided workers a self-administered survey to document symptoms and worker responses during the incident. Associations among categorical variables and experiencing symptoms were evaluated using Fisher's exact test. PARTICIPANTS: Twenty-six of 155 (17 percent) workers present at the refinery or driving on the access road the date the spill occurred completed the survey. MAIN OUTCOME MEASURE(S): Any self-reported symptom following exposure from the vinyl chloride release. RESULTS: Fifteen workers (58 percent) reported ≥1 symptom, most commonly headache (12, 46 percent). Three (12 percent) reported using respiratory protection. No differences in reporting symptoms were observed by location during the incident or by the building in which workers sheltered. Workers who moved from one shelter to another during the incident (ie, broke shelter) were more likely to report symptoms (Fisher's exact test, p=0.03); however, there are only limited data regarding vinyl chloride concentrations in shelters versus outside. CONCLUSIONS: Breaking shelter might result in greater exposures, and managers and health and safety officers of vulnerable facilities with limited physical access should consider developing robust shelter-in-place plans and alternate emergency egress plans. Workers should consider using respiratory protection if exiting a shelter is necessary during a chemical incident.

Severe Illness from Methyl Bromide Exposure at a Condominium Resort--U.S. Virgin Islands, March 2015.

On March 22, 2015, the Agency for Toxic Substances and Disease Registry (ATSDR) was notified by the U.S. Environmental Protection Agency (EPA) of four cases of suspected acute methyl bromide toxicity among family members vacationing at a condominium resort in the U.S. Virgin Islands. Methyl bromide is a pesticide that has been banned in the United States for use in homes and other residential settings. An investigation conducted by the U.S. Virgin Islands Department of Health (VIDOH), the U.S. Virgin Islands Department of Planning and Natural Resources (DPNR), and EPA confirmed that methyl bromide had been used as a fumigant on March 18 in the building where the family had been residing, 2 days before they were transported to the hospital; three family members had life-threatening illness. On March 25, 2015, a stop-use order for methyl bromide was issued by DPNR to the pest control company that had performed the fumigation. Subsequent investigation revealed that previous fumigation with methyl bromide had occurred on October 20, 2014, at the same condominium resort. In addition to the four ill family members, 37 persons who might have been exposed to methyl bromide as a result of the October 2014 or March 2015 fumigations were identified by VIDOH and ATSDR. Standardized health questionnaires were administered to 16 of the 20 persons for whom contact information was available; six of 16 had symptoms consistent with methyl bromide exposure, including headache and fatigue. Pest control companies should be aware that use of methyl bromide is banned in homes and other residential settings, and clinicians should be aware of the toxicologic syndrome that exposure to methyl bromide can cause.

Persons injured during acute chemical incidents­Hazardous Substances Emergency Events Surveillance, nine states, 1999-2008.

PROBLEM/CONDITION: Persons exposed to chemicals during acute chemical incidents (i.e., uncontrolled or illegal release or threatened release of hazardous substances lasting <72 hours) can experience both acute and chronic health effects. Surveillance of toxic substance incidents provides data that can be used to prevent future incidents and improve the emergency response to those that occur, leading to a decrease in morbidity and mortality from chemical releases. REPORTING PERIOD: 1999-2008 DESCRIPTION OF SYSTEM: The Hazardous Substances Emergency Events Surveillance (HSEES) system was operated by the Agency for Toxic Substances and Disease Registry (ATSDR) during January 1991-September 2009 to describe the public health consequences of chemical releases and to develop activities aimed at reducing the harm. This report summarizes the data collected on injured persons from the nine states (Colorado, Iowa, Minnesota, New York, North Carolina, Oregon, Texas, Washington, and Wisconsin) that participated in HSEES during its last 10 full years of data collection (1999-2008). RESULTS: A total of 57,975 chemical incidents were reported by these states during the 10-year surveillance period. In 4,621 (8%) of these incidents, 15,506 persons were injured. Among them, 354 deaths occurred. The most commonly reported category of injured persons included employees of the responsible party (7,616 [49%]), members of the general public (4,737 [31%]), students exposed at school (1,730 [11%]), and responders to the incident (1,398 [9%]). Deaths occurred among members of the general public (190 [54%]), employees (154 [44%]), and responders (10 [3%]). The most frequent health effects experienced as a result of these incidents included respiratory irritation (7,443), dizziness or central nervous system problems (3,186), and headache (3,167). The three chemicals associated with the largest number of persons injured were carbon monoxide (2,364), ammonia (1,153), and chlorine (763). INTERPRETATION: Company employees, followed by members of the general public, are frequently injured in acute chemical incidents. The chemicals most often associated with these injuries are carbon monoxide, ammonia, and chlorine, all of which are hazardous gases that can be found in various locations including schools and homes. Respiratory irritation is the most common health effect. PUBLIC HEALTH IMPLICATIONS: By understanding the types of persons injured in chemical release incidents, as well as how they are injured and the injuries sustained, prevention outreach activities can be focused to protect the health of these groups in the future. Improved awareness among and training for not just employees but also the public is needed, particularly regarding carbon monoxide, ammonia, and chlorine. Appropriate measures to provide protection from respiratory effects of chemical incidents could prevent injuries.