Evaluating the Effectiveness of State-Level Policies on Childhood Blood Lead Testing Rates.

CONTEXT: Lead exposure can harm nearly every organ in the human body. Millions of US children are exposed to lead hazards. Identifying lead-exposed children using blood lead testing is essential for connecting them to appropriate follow-up services. However, blood lead testing is not consistently conducted for at-risk children. Thus, determining which policies help improve blood lead testing rates is essential. OBJECTIVE: This analysis provides critical evidence to better understand which state-level policies are more effective at increasing childhood blood lead testing rates. These include metrics, incentives, other managed care organization guidance, provider guidelines, mandatory reporting of results to state health departments, data sharing between Medicaid and other state agencies, and proof of testing for school enrollment. DESIGN: This analysis included 33 states with complete data on the number of children tested for blood lead in 2017-2018 as reported to the Centers for Disease Control and Prevention. Linear regression modeling was conducted to examine associations between testing rates and the aforementioned policies. Fully adjusted models included percentages of the population living in pre-1980 housing, younger than 6 years with Medicaid coverage, and foreign-born. RESULTS: Strongest unadjusted and adjusted regression coefficients were observed for requiring proof of testing for school enrollment (ß = .12, P = .03) and metrics (ß = .06, P = .01), respectively. CONCLUSION: Policies associated with higher childhood blood lead testing rates can be used by policy makers; local, state, and federal public health agencies; professional organizations; nonprofit organizations; and others to inform development and implementation of additional policies to increase childhood blood lead testing.

Update of the Blood Lead Reference Value - United States, 2021.

The negative impact of lead exposure on young children and those who become pregnant is well documented but is not well known by those at highest risk from this hazard. Scientific evidence suggests that there is no known safe blood lead level (BLL), because even small amounts of lead can be harmful to a child's developing brain (1). In 2012, CDC introduced the population-based blood lead reference value (BLRV) to identify children exposed to more lead than most other children in the United States. The BLRV should be used as a guide to 1) help determine whether medical or environmental follow-up actions should be initiated for an individual child and 2) prioritize communities with the most need for primary prevention of exposure and evaluate the effectiveness of prevention efforts. The BLRV is based on the 97.5th percentile of the blood lead distribution in U.S. children aged 1-5 years from National Health and Nutrition Examination Survey (NHANES) data. NHANES is a complex, multistage survey designed to provide a nationally representative assessment of health and nutritional status of the noninstitutionalized civilian adult and child populations in the United States (2). The initial BLRV of 5 µg/dL, established in 2012, was based on data from the 2007-2008 and 2009-2010 NHANES cycles. Consistent with recommendations from a former advisory committee, this report updates CDC's BLRV in children to 3.5 µg/dL using NHANES data derived from the 2015-2016 and 2017-2018 cycles and provides helpful information to support adoption by state and local health departments, health care providers (HCPs), clinical laboratories, and others and serves as an opportunity to advance health equity and environmental justice related to preventable lead exposure. CDC recommends that public health and clinical professionals focus screening efforts on populations at high risk based on age of housing and sociodemographic risk factors. Public health and clinical professionals should collaborate to develop screening plans responsive to local conditions using local data. In the absence of such plans, universal BLL testing is recommended. In addition, jurisdictions should follow the Centers for Medicare & Medicaid Services requirement that all Medicaid-enrolled children be tested at ages 12 and 24 months or at age 24-72 months if they have not previously been screened (3).

The Flint Water Crisis: A Coordinated Public Health Emergency Response and Recovery Initiative.

CONTEXT: The City of Flint was already distressed because of decades of financial decline when an estimated 140 000 individuals were exposed to lead and other contaminants in drinking water. In April 2014, Flint's drinking water source was changed from Great Lakes' Lake Huron (which was provided by the Detroit Water and Sewerage Department) to the Flint River without necessary corrosion control treatment to prevent lead release from pipes and plumbing. Lead exposure can damage children's brains and nervous systems, lead to slow growth and development, and result in learning, behavior, hearing, and speech problems. After the involvement of concerned residents and independent researchers, Flint was reconnected to the Detroit water system on October 16, 2015. A federal emergency was declared in January 2016. PROGRAM: The Centers for Disease Control and Prevention provided assistance and support for response and recovery efforts including coordinating effective health messaging; assessing lead exposure; providing guidance on blood lead screening protocols; and identifying and linking community members to appropriate follow-up services.In response to the crisis in Flint, Congress funded the Centers for Disease Control and Prevention to establish a federal advisory committee; enhance Childhood Lead Poisoning Prevention Program activities; and support a voluntary Flint lead exposure registry. The registry, funded through a grant to Michigan State University, is designed to identify eligible participants and ensure robust registry data; monitor health, child development, service utilization, and ongoing lead exposure; improve service delivery to lead-exposed individuals; and coordinate with other community and federally funded programs in Flint. The registry is also collaborating to make Flint "lead-free" and to share best practices with other communities. DISCUSSION: The Flint water crisis highlights the need for improved risk communication strategies, and environmental health infrastructure, enhanced surveillance, and primary prevention to identify and respond to environmental threats to the public's health. Collecting data is important to facilitate action and decision making to prevent lead poisoning. Partnerships can help guide innovative strategies for primary lead prevention, raise awareness, extend outreach and communication efforts, and promote a shared sense of ownership.

Evaluation of contaminated drinking water and male breast cancer at Marine Corps Base Camp Lejeune, North Carolina: a case control study.

BACKGROUND: Solvents contaminated drinking water supplies at Marine Corps Base Camp Lejeune during 1950s-1985. METHODS: We conducted a case-control study among Marines to evaluate associations between residential exposure to contaminated drinking water at Camp Lejeune and male breast cancer risk. The study included 71 male breast cancer cases and 373 controls identified from the Department of Veteran's Affairs (VA) cancer registry whose military personnel records were available. Controls were selected from cancers not known to be associated with solvent exposure and included 270 skin cancers, 71 mesotheliomas, and 32 bone cancers. Base assignment and risk factor information came from military personnel and VA records. Groundwater contaminant fate/transport and distribution system models provided monthly estimated residential contaminant levels. We conducted exact logistic regression using the 50th percentile level among exposed controls to create low and high exposure categories. We calculated 95% confidence intervals (CIs) to indicate precision of effect estimates. Exploratory analyses used proportional hazards methods to evaluate associations between exposures and age at diagnosis. RESULTS: After adjusting for age at diagnosis, race, and service in Vietnam, the odds ratio (OR) for ever stationed at Camp Lejeune was 1.14 (95% CI: 0.65, 1.97). Adjusted ORs for high residential cumulative exposures to tetrachloroethylene (PCE), t-1,2 dichloroethylene (DCE), and vinyl chloride were 1.20 [95% CI: 0.16-5.89], 1.50 [95% CI: 0.30-6.11], 1.19 [95% CI: 0.16-5.89], respectively, with a monotonic exposure response relationship for PCE only. However these results were based on two or three cases in the high cumulative exposure categories. Ever stationed at Camp Lejeune and high cumulative exposures to trichloroethylene (TCE), PCE, DCE and vinyl chloride were associated with earlier age at onset for male breast cancer; hazard ratios ranged from 1.4-2.7 with wide confidence intervals for cumulative exposure variables. CONCLUSION: Findings suggested possible associations between male breast cancer and being stationed at Camp Lejeune and cumulative exposure to PCE, DCE, and vinyl chloride. TCE, PCE, DCE and vinyl chloride cumulative exposures showed possible associations with earlier age at onset of male breast cancer. However, this study was limited by small numbers of cases in high exposure categories.

Temporal trends of acute chemical incidents and injuries­Hazardous Substances Emergency Events Surveillance, nine states, 1999-2008.

PROBLEM/CONDITION: Widespread use of hazardous chemicals in the United States is associated with unintentional acute chemical incidents (i.e., uncontrolled or illegal release or threatened release of hazardous substances lasting <72 hours). Efforts by industries, government agencies, academics, and others aim to reduce chemical incidents and the public health consequences, environmental damage, and economic losses; however, incidents are still prevalent. 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 temporal trends in the numbers of incidents, injured persons, deaths, and evacuations 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 incidents and 15,506 injured persons, including 354 deaths, were reported. During the surveillance period, several trends were observed: a slight overall decrease occurred in incidents for fixed facilities (R² = 0.6) and an increasing trend in deaths (R² = 0.7) occurred, particularly for the general public (R² = 0.9). The number of incidents increased in the spring during March-June, and a decrease occurred in the remainder of the year (R² = 0.5). A decreasing trend in incidents occurred during Monday-Sunday (R² = 0.7) that was similar to that for the number of injured persons (R² = 0.6). The highest number of incidents occurred earlier in the day (6:00 a.m.-11:59 a.m.) and then decreased as the day went on (R² = 0.9); this trend was similar for the number of injured persons (R² = 1.0). INTERPRETATION: Chemical incidents continue to affect public health and appear to be a growing problem for the general public. The number of incidents and injuries varied by month, day of week, and time of day and likely was influenced by other factors such as weather and the economy. PUBLIC HEALTH IMPLICATIONS: Public and environmental health and safety practitioners, worker representatives, emergency planners, preparedness coordinators, industries, emergency responders, and others can use the findings in this report to prepare for and prevent chemical incidents and injuries. Specifically, knowing when to expect the most incidents and injuries can guide preparedness and prevention efforts. In addition, new or expanded efforts and outreach to educate consumers who could be exposed to chemicals are needed (e.g., education about the dangers of carbon monoxide poisoning for consumers in areas likely to experience weather-related power outages). Redirection of efforts such as promoting inherently safer technologies should be explored to reduce or eliminate the hazards completely.

Evaluation of contaminated drinking water and preterm birth, small for gestational age, and birth weight at Marine Corps Base Camp Lejeune, North Carolina: a cross-sectional study.

BACKGROUND: Births during 1968-1985 at Camp Lejeune were exposed to drinking water contaminated with trichloroethylene (TCE), tetrachloroethylene (PCE), and benzene. METHODS: We conducted a cross-sectional study to evaluate associations between residential prenatal exposure to contaminated drinking water at Camp Lejeune during 1968-1985 and preterm birth, small for gestational age (SGA), term low birth weight (TLBW), and mean birth weight (MBW) deficit. Birth certificates identified mothers residing at Camp Lejeune at delivery. We analyzed exposure data for the entire pregnancy and individual trimesters. For each period examined, births were categorized as unexposed if mothers did not reside at Camp Lejeune or if their residence on base received uncontaminated drinking water. Ground water contaminant fate/transport and distribution system models provided monthly estimated contaminant levels at residences. For PCE and TCE, the exposed group was divided into four levels: < median value, ≥ median value, ≥75th percentile, and ≥90th percentile. For benzene, the exposed group was categorized as <1 part per billion (ppb) versus ≥1 ppb because of sparse data. Magnitude of effect estimates and exposure response relationships were used to assess associations. Confidence intervals (CIs) indicated precision of estimates. RESULTS: For the highest TCE exposure category during the entire pregnancy, odds ratios (ORs) were 1.5 (95% CI: 1.2, 1.9) and 1.3 (95% CI: 0.8, 2.2) for SGA and TLBW, respectively, and reduced MBW ß = -78.3 g (95% CI: -115.0, -41.7). The OR =1.3 (95% CI: 1.0, 1.6) for preterm birth and the highest PCE exposure category during the entire pregnancy. Monotonic exposure-response relationships were observed for benzene exposure during the entire pregnancy and TLBW (highest category OR =1.5, 85% CI: 0.9, 2.3). Although a monotonic association between benzene and adjusted MBW difference was also observed (highest category ß = -36.2 g, 95% CI: -72.3, -0.1), the association disappeared when TCE was also added to the model. We found no evidence suggesting any other associations between outcomes and exposures. CONCLUSION: Findings suggested associations between in utero exposures to TCE and SGA, TLBW and reduced MBW; benzene and TLBW; and PCE and preterm birth.

Mortality study of civilian employees exposed to contaminated drinking water at USMC Base Camp Lejeune: a retrospective cohort study.

BACKGROUND: Two drinking water systems at U.S. Marine Corps Base Camp Lejeune, North Carolina were contaminated with solvents during 1950s-1985. METHODS: We conducted a retrospective cohort mortality study of 4,647 civilian, full-time workers employed at Camp Lejeune during 1973-1985 and potentially exposed to contaminated drinking water. We selected a comparison cohort of 4,690 Camp Pendleton workers employed during 1973-1985 and unexposed to contaminated drinking water. Mortality follow-up period was 1979-2008. Cause-specific standardized mortality ratios utilized U.S. age-, sex-, race-, and calendar period-specific mortality rates as reference. We used survival analysis to compare mortality rates between Camp Lejeune and Camp Pendleton workers and assess the effects of estimated cumulative contaminant exposures within the Camp Lejeune cohort. Ground water contaminant fate/transport and distribution system models provided monthly estimated contaminant levels in drinking water serving workplaces at Camp Lejeune. The confidence interval (CI) indicated precision of effect estimates. RESULTS: Compared to Camp Pendleton, Camp Lejeune workers had mortality hazard ratios (HRs) >1.50 for kidney cancer (HR = 1.92, 95% CI: 0.58, 6.34), leukemias (HR = 1.59, 95% CI: 0.66, 3.84), multiple myeloma (HR = 1.84, 95% CI: 0.45, 7.58), rectal cancer (HR = 1.65, 95% CI: 0.36, 7.44), oral cavity cancers (HR = 1.93, 95% CI: 0.34, 10.81), and Parkinson's disease (HR = 3.13, 95% CI: 0.76, 12.81). Within the Camp Lejeune cohort, monotonic exposure-response relationships were observed for leukemia and vinyl chloride and PCE, with mortality HRs at the high exposure category of 1.72 (95% CI: 0.33, 8.83) and 1.82 (95% CI: 0.36, 9.32), respectively. Cumulative exposures were above the median for most deaths from cancers of the kidney, esophagus, rectum, prostate, and Parkinson's disease, but small numbers precluded evaluation of exposure-response relationships. CONCLUSION: The study found elevated HRs in the Camp Lejeune cohort for several causes of death including cancers of the kidney, rectum, oral cavity, leukemias, multiple myeloma, and Parkinson's disease. Only 14% of the Camp Lejeune cohort died by end of follow-up, producing small numbers of cause-specific deaths and wide CIs. Additional follow-up would be necessary to comprehensively assess drinking water exposure effects at the base.

Evaluation of mortality among marines and navy personnel exposed to contaminated drinking water at USMC base Camp Lejeune: a retrospective cohort study.

BACKGROUND: Two drinking water systems at U.S. Marine Corps Base Camp Lejeune, North Carolina were contaminated with solvents during 1950s-1985. METHODS: We conducted a retrospective cohort mortality study of Marine and Naval personnel who began service during 1975-1985 and were stationed at Camp Lejeune or Camp Pendleton, California during this period. Camp Pendleton's drinking water was uncontaminated. Mortality follow-up was 1979-2008. Standardized Mortality Ratios were calculated using U.S. mortality rates as reference. We used survival analysis to compare mortality rates between Camp Lejeune (N = 154,932) and Camp Pendleton (N = 154,969) cohorts and assess effects of cumulative exposures to contaminants within the Camp Lejeune cohort. Models estimated monthly contaminant levels at residences. Confidence intervals (CIs) indicated precision of effect estimates. RESULTS: There were 8,964 and 9,365 deaths respectively, in the Camp Lejeune and Camp Pendleton cohorts. Compared to Camp Pendleton, Camp Lejeune had elevated mortality hazard ratios (HRs) for all cancers (HR = 1.10, 95% CI: 1.00, 1.20), kidney cancer (HR = 1.35, 95% CI: 0.84, 2.16), liver cancer (HR = 1.42, 95% CI: 0.92, 2.20), esophageal cancer (HR = 1.43 95% CI: 0.85, 2.38), cervical cancer (HR = 1.33, 95% CI: 0.24, 7.32), Hodgkin lymphoma (HR = 1.47, 95% CI: 0.71, 3.06), and multiple myeloma (HR = 1.68, 95% CI: 0.76, 3.72). Within the Camp Lejeune cohort, monotonic categorical cumulative exposure trends were observed for kidney cancer and total contaminants (HR, high cumulative exposure = 1.54, 95% CI: 0.63, 3.75; log10 ß = 0.06, 95% CI: -0.05, 0.17), Hodgkin lymphoma and trichloroethylene (HR, high cumulative exposure = 1.97, 95% CI: 0.55, 7.03; ß = 0.00005, 95% CI: -0.00003, 0.00013) and benzene (HR, high cumulative exposure = 1.94, 95% CI: 0.54, 6.95; ß = 0.00203, 95% CI: -0.00339, 0.00745). Amyotrophic Lateral Sclerosis (ALS) had HR = 2.21 (95% CI: 0.71, 6.86) at high cumulative vinyl chloride exposure but a non-monotonic exposure-response relationship (ß = 0.0011, 95% CI: 0.0002, 0.0020). CONCLUSION: The study found elevated HRs at Camp Lejeune for several causes of death including cancers of the kidney, liver, esophagus, cervix, multiple myeloma, Hodgkin lymphoma and ALS. CIs were wide for most HRs. Because <6% of the cohort had died, long-term follow-up would be necessary to comprehensively assess effects of drinking water exposures at the base.

Evaluation of exposure to contaminated drinking water and specific birth defects and childhood cancers at Marine Corps Base Camp Lejeune, North Carolina: a case-control study.

BACKGROUND: Drinking water supplies at Marine Corps Base Camp Lejeune were contaminated with trichloroethylene, tetrachloroethylene, benzene, vinyl chloride and trans-1,2-dichloroethylene during 1968 through 1985. METHODS: We conducted a case control study to determine if children born during 1968-1985 to mothers with residential exposure to contaminated drinking water at Camp Lejeune during pregnancy were more likely to have childhood hematopoietic cancers, neural tube defects (NTDs), or oral clefts. For cancers, exposures during the first year of life were also evaluated. Cases and controls were identified through a survey of parents residing on base during pregnancy and confirmed by medical records. Controls were randomly sampled from surveyed participants who had a live birth without a major birth defect or childhood cancer. Groundwater contaminant fate and transport and distribution system models provided estimates of monthly levels of drinking water contaminants at mothers' residences. Magnitude of odds ratios (ORs) was used to assess associations. Confidence intervals (CIs) were used to indicate precision of ORs. We evaluated parental characteristics and pregnancy history to assess potential confounding. RESULTS: Confounding was negligible so unadjusted results were presented. For NTDs and average 1st trimester exposures, ORs for any benzene exposure and for trichloroethylene above 5 parts per billion were 4.1 (95% CI: 1.4-12.0) and 2.4 (95% CI: 0.6-9.6), respectively. For trichloroethylene, a monotonic exposure response relationship was observed. For childhood cancers and average 1st trimester exposures, ORs for any tetrachloroethylene exposure and any vinyl chloride exposure were 1.6 (95% CI: 0.5-4.8), and 1.6 (95% CI: 0.5-4.7), respectively. The study found no evidence suggesting any other associations between outcomes and exposures. CONCLUSION: Although CIs were wide, ORs suggested associations between drinking water contaminants and NTDs. ORs suggested weaker associations with childhood hematopoietic cancers.

Using Chemical Release Surveillance Data to Evaluate the Public Health Impacts of Chlorine and Its Alternatives.

BACKGROUND: More than 80 million Americans may be at risk of a chemical exposure because they live near one of the 101 most hazardous chemical facilities or near routes used to transport hazardous chemicals. One approach to hazard reduction is to use less toxic alternatives. Chlorine, one of the chemicals posing the greatest public health danger, has several alternatives depending on the application. METHODS: We analyzed data collected during 1993-2008 by 17 state health departments participating in the Agency for Toxic Substances and Disease Registry's (ATSDR) active chemical incident surveillance program. We conducted descriptive analyses to evaluate whether five chlorine alternatives (calcium hypochlorite, hydrogen peroxide, sodium chlorate, sodium hydrosulfite, and sodium hypochlorite) resulted in less severe incidents. We used chi square and z-score analyses to test significance, where appropriate. RESULTS: During 1993-2008, 2040 incidents involved chlorine, and 1246 incidents involved chlorine alternatives. Nearly 30% of chlorine releases resulted in injured persons, as compared to 13% of chlorine alternatives that resulted in injury. Although similar proportions of persons injured in chlorine or chlorine alternative releases were treated on scene (18% and 14%, respectively) and at a hospital (58% and 60%, respectively), there was a greater proportion of hospital admissions following chlorine releases than there was following releases of chlorine alternatives (10 % vs. 4%) (p < 0.01). There were significantly fewer victims per release for hydrogen peroxide (0.2) than there were for chlorine (1.3) in paper manufacturing (p < 0.01). CONCLUSION: Exposures to these five potential chlorine alternatives resulted in a lower proportion of exposed persons requiring hospital admission. To reduce acute public health injuries associated with chemical exposures, users should consider a chlorine alternative when such a substitution is reasonable.

The 2009 National Environmental Public Health Conference: one model for planning green and healthy conferences.

The Centers for Disease Control and Prevention's National Center for Environmental Health and the Agency for Toxic Substances and Disease Registry committed to making their 2009 National Environmental Public Health Conference a model for green and healthy conferences. The conference included increased opportunities for physical activity, both as part of conference events and for transportation to the conference. In addition, conference meals were healthy and sustainably sourced. The conference also implemented intuitive, accessible recycling; online scheduling and evaluation to minimize hard-copy materials; and the purchase of carbon offsets to reduce the unwanted environmental impact of the conference. Public health professionals have an opportunity and obligation to support healthy behaviors at their events and to serve as leaders in this area. Facilitating healthy and sustainable choices is in alignment with goals for both public health and broader social issues-such as environmental quality-that have a direct bearing on public health.

A U.S. partnership with India and Poland to track acute chemical releases to serve public health.

We describe a collaborative effort between the U.S., India, and Poland to track acute chemical releases during 2005-2007. In all three countries, fixed facility events were more common than transportation-related events; manufacturing and transportation/warehousing were the most frequently involved industries; and equipment failure and human error were the primary contributing factors. The most commonly released non-petroleum substances were ammonia (India), carbon monoxide (U.S.) and mercury (Poland). More events in India (54%) resulted in victims compared with Poland (15%) and the U.S. (9%). The pilot program showed it is possible to successfully conduct international surveillance of acute hazardous substances releases with careful interpretation of the findings.

Public health consequences on vulnerable populations from acute chemical releases.

Data from a large, multi-state surveillance system on acute chemical releases were analyzed to describe the type of events that are potentially affecting vulnerable populations (children, elderly and hospitalized patients) in order to better prevent and plan for these types of incidents in the future. During 2003-2005, there were 231 events where vulnerable populations were within » mile of the event and the area of impact was greater than 200 feet from the facility/point of release. Most events occurred on a weekday during times when day care centers or schools were likely to be in session. Equipment failure and human error caused a majority of the releases. Agencies involved in preparing for and responding to chemical emergencies should work with hospitals, nursing homes, day care centers, and schools to develop policies and procedures for initiating appropriate protective measures and managing the medical needs of patients. Chemical emergency response drills should involve the entire community to protect those that may be more susceptible to harm.

Hazardous substances releases associated with Hurricanes Katrina and Rita in industrial settings, Louisiana and Texas.

The scientific literature concerning the public health response to the unprecedented hurricanes striking the Gulf Coast in August and September 2005 has focused mainly on assessing health-related needs and surveillance of injuries, infectious diseases, and other illnesses. However, the hurricanes also resulted in unintended hazardous substances releases in the affected states. Data from two states (Louisiana and Texas) participating in the Hazardous Substances Emergency Events Surveillance (HSEES) system were analyzed to describe the characteristics of hazardous substances releases in industrial settings associated with Hurricanes Katrina and Rita. HSEES is an active multi-state Web-based surveillance system maintained by the Agency for Toxic Substances and Disease Registry (ATSDR). In 2005, 166 hurricane-related hazardous substances events in industrial settings in Louisiana and Texas were reported. Most (72.3%) releases were due to emergency shut downs in preparation for the hurricanes and start-ups after the hurricanes. Emphasis is given to the contributing causal factors, hazardous substances released, and event scenarios. Recommendations are made to prevent or minimize acute releases of hazardous substances during future hurricanes, including installing backup power generation, securing equipment and piping to withstand high winds, establishing procedures to shutdown process operations safely, following established and up-to-date start-up procedures and checklists, and carefully performing pre-start-up safety reviews.

Are nitrate levels in groundwater stable over time?

Epidemiologists often use a retrospective study design to examine for associations between an exposure and the occurrence of adverse health effects. Several of these studies used this approach to examine for an association between elevated levels of nitrate in drinking water and related health effects such as methemoglobinemia, cancer, neural tube effects, or spontaneous abortions. Often, data on exposures that occurred before these health outcomes were not available. Consequently, researchers use measurements of exposures at the time of the study to represent exposures that occurred before people developed these conditions. An opportunity to examine the stability of nitrate in water occurred during a survey of private water wells in nine Midwestern states. In this survey, water samples from 853 homes with drilled wells were collected in May 1994 and in September 1995 and nitrate-nitrogen (nitrate-N) was measured by the colorimetric cadmium reduction method. Nitrate-N levels from the same well over time were assessed by a mixed-effects analysis of variance. Analysis showed no significant difference in between the initial level and those measured 16 months later. Furthermore, analysis showed that most of the variance in the nitrate concentrations in well water was due to well-to-well variation (89%) rather than to residual error (12%). This observation showed that a single measurement of nitrate in water from drilled wells could represent longer periods of exposure.

Human error and time of occurrence in hazardous material events in mining and manufacturing.

Human error has played a role in several large-scale hazardous materials events. To assess how human error and time of occurrence may have contributed to acute chemical releases, data from the Hazardous Substances Emergency Events Surveillance (HSEES) system for 1996-2003 were analyzed. Analyses were restricted to events in mining or manufacturing where human error was a contributing factor. The temporal distribution of releases was also evaluated to determine if the night shift impacted releases due to human error. Human error-related events in mining and manufacturing resulted in almost four times as many events with victims and almost three times as many events with evacuations compared with events in these industries where human error was not a contributing factor (10.3% versus 2.7% and 11.8% versus 4.5%, respectively). Time of occurrence of events attributable to human error in mining and manufacturing showed a widespread distribution for number of events, events with victims and evacuations, and hospitalizations and deaths, without apparent increased occurrence during the night shift. Utilizing human factor engineering in both front-end ergonomic design and retrospective incident investigation provides one potential systematic approach that may help minimize human error in workplace-related acute chemical releases and their resulting injuries.

Surveillance of hazardous substances releases due to system interruptions, 2002.

The Hazardous Substances Emergency Events Surveillance (HSEES) system collected information on 9014 acute hazardous substance releases in 15 participating states in 2002. There were 3749 fixed-facility manufacturing events, of which 2100 involved "interruptions" to normal processing and 1649 "comparisons" that did not involve interruption. Equipment failure (69%) or intentional acts (20%) were the main root factor. Many events occurred in October and November in three states (Texas, Louisiana, and New Jersey), in three manufacturing industries (industrial and miscellaneous chemicals; petroleum refining; and plastics, synthetics, and resins). In interruption events, the substance categories most often released were mixtures, other inorganic substances, and volatile organic compounds and those most often causing injury were acids, chlorine, bases, and ammonia. Comparison events resulted in more acutely injured persons (408 versus 59) and more evacuees (11,318 versus 335) than interruption events and therefore may receive more public health attention. Because of the large number of interruption events, targeted prevention activities, including management of change procedures, lessons-learned implementation, process hazards analysis, and appropriate protection for workers could be economically advantageous and improve environmental quality. Efforts should focus on the identified areas of greater occurrence. The relationship of weather and equipment failure with interruption events needs further investigation.

Analyzing acute-chemical-release data to describe chemicals that may be used as weapons of terrorism.

The authors analyzed a database of acute chemical releases to describe characteristics of chemicals that may be used as weapons of terrorism. Chemicals of primary concern (Priority I) on the Chemical Terrorism Listing of the Centers for Disease Control and Prevention were cross-referenced with data for 1993-2002 from the Hazardous Substances Emergency Events Surveillance (HSEES) system. HSEES captured 58,043 single-substance releases of 2,366 chemicals during this time period. The 48 Priority I chemicals accounted for 11,567 (20 percent) of the releases, while representing only 2.0 percent of reported chemicals. Events involving Priority I chemicals resulted in twice as many victims, more injured members of the general public, more victims treated at hospitals, a higher frequency of respiratory irritation, more evacuations, more people evacuated per event, and more decontaminations than did all other HSEES events. Industry, responders, and hospitals should consider the results of this analysis in preparing for and responding to acute chemical releases.

The role of adverse weather conditions in acute releases of hazardous substances, Texas, 2000-2001.

High winds, flooding, lightning, and other phenomena associated with adverse weather can cause power failures, equipment damage, and process upsets resulting in chemical releases. Of the 5000 events in Texas that were reported to the Hazardous Substances Emergency Events Surveillance (HSEES) system during 2000-2001, adverse weather conditions contributed to 110 (2%) events. Rain was the most frequent adverse weather condition. Most events to which adverse weather conditions contributed occurred during June or September; these months correspond with the high temperature and hurricane season in Texas. Most events occurred in coastal counties with large numbers of industrial facilities. Three industries reported the majority of events: industrial and miscellaneous chemicals manufacturing; petroleum refining; and plastics, synthetics, and resin manufacturing. Power failures were associated more often with adverse weather-related events than with nonweather-related events. Releases occurred most commonly from ancillary process equipment and process vessels. Events associated with adverse weather-related conditions involved nine victims. System and process design improvements, such as improved backup power generation and redesigned secondary containment systems, could be explored to reduce the potential negative effects of severe weather.

Long-term neurobehavioral health effects of methyl parathion exposure in children in Mississippi and Ohio.

Methyl parathion (MP), an organophosphate pesticide licensed only for agricultural uses, was sprayed illegally for pest control in Mississippi and Ohio residences. To evaluate the association between MP exposure and neurobehavioral development, we assessed children 6 years or younger at the time of the spraying and local comparison groups of unexposed children using the Pediatric Environmental Neurobehavioral Test Battery (PENTB). The PENTB is composed of informant-based procedures (parent interview and questionnaires) and performance-based procedures (neurobehavioral tests for children 4 years or older) that evaluate cognitive, motor, sensory, and affect domains essential to neurobehavioral assessment. Children were classified as exposed or unexposed on the basis of urinary para-nitrophenol levels and environmental wipe samples for MP. Exposed children had more difficulties with tasks involving short-term memory and attention. Additionally, parents of exposed children reported that their children had more behavioral and motor skill problems than did parents of unexposed children. However, these effects were not consistently seen at both sites. There were no differences between exposed and unexposed children in tests for general intelligence, the integration of visual and motor skills, and multistep processing. Our findings suggest that MP might be associated with subtle changes to short-term memory and attention and contribute to problems with motor skills and some behaviors, but the results of the study are not conclusive.