Since the government action on the removal of lead from gasoline in the 1970s, children's environmental health research and policy measures have expanded greatly. Education and outreach campaigns urge parents to ensure their homes are lead free and to check for the presence of radon, mold, and other potential environmental hazards. However, children also spend a good portion of their days in school environments, with the conditions of many schools being so poor that Lloyd Kolbe, founding and former director of the U.S. Centers for Disease Control and Prevention's (CDC) Division of Adolescent and School Health, has referred to them as “America's largest unaddressed children's health crisis” (Healthy Schools Network, 2005, p. ii.).
According to 2008 National Center for Education Statistics (NCES) data, there are approximately 132,000 public and private schools in the United States, employing over 7 million adults and enrolling 56 million children (NCES, 2008). Twenty percent of the U.S. population attends elementary and secondary schools, many of which are very densely occupied (U.S. Environmental Protection Agency [EPA], 2002).
In 2006, a national collaborative report entitled Lessons Learned (Healthy Schools Network, 2006) estimated that 32 million U.S. children were at risk due solely to school conditions. These conditions include the presence of old and peeling paint, asbestos, mold, poor indoor air quality, and pesticides, as well as possible preexisting on-site or off-site contamination. According to the EPA (2002), one half of U.S. schools have indoor environmental quality problems. Indoor concentrations of pollutants are commonly three to five times higher than outdoor concentrations due to chemicals found in some conventional cleaning products, improper cleaning procedures, defective or ineffective climate control (HVAC) systems, interior finishes, exterior pollutants, personal care products, and renovation projects (EPA, 2002). Contamination is portable as well and can be brought inside from outdoor exposures.
Special Needs on the Rise
Childhood exposures to environmental toxins have been associated with various cognitive and behavioral impairments, immune dysfunction, adverse reproductive and developmental effects, cardio-respiratory illnesses, and cancer (Greater Boston Physicians for Social Responsibility [GBPSR], 2000; Landrigan, Needleman, & Landrigan, 2002; Rudant et al., 2007; Salam, Li, Langholz, & Gilliland, 2004). One out of every 10 school-aged children, or over 6.7 million children under 18 years of age, has asthma, and between 1977 and 1994 the number of children in special education increased 191% (Akinbami, 2006; American Lung Assocation, 2009; GBPSR, 2000). The prevalence of diagnosed learning disabilities, autism spectrum disorders, and attention deficit hyperactivity disorder in children has increased dramatically nationwide (GBPSR, 2000). Environmental contaminants, especially those that affect indoor air quality, have also been linked to increased allergies and sensitivities, rashes, headaches, and other symptoms, often referred to as sick building syndrome (EPA, 2008).
Environmental toxic exposures have also been linked with decreased IQ. One study reported that, on average, a 1-µg/dL increase in blood lead results in a decrease of 0.46 IQ points (Canfield et al., 2003). This rate of decline in intellectual functioning appears even greater (1.37 IQ points lost per 1-µg/dL increase in blood lead) among children with blood lead levels below, rather than above, the CDC recommended level of 10 µg/dL (Canfield et al., 2003). Taking into account this increased effect at lower body burdens, more children may be at greater risk of harm from lead exposure than previously believed.
Lead has been relatively well researched with regard to its adverse effect on IQ. Yet, other toxicants and combinations of chemicals have also been associated with lowered cognitive functioning. For example, a 2009 Columbia University study found that exposure to polycyclic aromatic hydrocarbons, chemicals released into the air from burning of coal, diesel, oil, gas, and other substances, such as tobacco, can also inversely impact IQ in the developing brain. Schools that have idling buses or are close to major highways may have higher levels of polycyclic aromatic hydrocarbons in the indoor air (Perera et al., 2009).
Researchers have found that lowered IQ, even by just a few points, negatively impacts an individual's future earnings (Schwartz, 1994). Other hidden expenses of unaddressed children's environmental health concerns include parents' lost wages due to medical and therapeutic expenses and missed work and the costs to school districts and taxpayers of postconstruction remediation efforts, which often far exceed the costs of precautionary or proactive measures (Center for Health Environment and Justice [CHEJ], 2005). Additonal expenses may arise from lawsuits brought against school districts by affected families. Indeed, the adverse effects of childhood environmental exposures, such as lead poisoning–induced aggression and violence, affect society as a whole. It is estimated that anywhere from $4.6 to $18.4 billion in costs of neurobehavioral disorders alone in the U.S. are attributable to environmental toxicants (Landrigan, Schechter, Lipton, Fahs, & Schwartz, 2002).
Between 1976 and 1994, the average blood lead levels of U.S. children plunged from 16 µg/dL to 3.2 µg/dL, primarily as a result of the removal of lead from products such as gasoline and paint in the 1970s (Gilbert & Weiss, 2006). Grosse, Matte, Schwartz, and Jackson (2002) estimated that U.S. preschool-aged children in the late 1990s had IQs that were, on average, 2.2–4.7 points higher than they would have been had their blood lead distribution matched that observed among U.S. preschool-aged children in the late 1970s. Each 1-point increase in an individual's IQ has been associated with a 1.76% to 2.37% increase in future earning potential, and the researchers estimated that the economic benefit for each year's cohort of 3.8 million 2-year-old children ranged from $110 billion to $319 billion (in 2000 dollars; Gross et al., 2002). This represents a truly significant public health triumph in the United States, yet the problems of lead exposure continue to persist for many children. The CDC estimates that there remain approximately 310,000 children aged 1–5 years with BLLs greater than 10 µg/dL, the upper limit of what is considered an acceptable level, which is arguably too high (CDC, 2005; Gilbert & Weiss, 2006).
Children's Unique Vulnerabilities
Although adults also work in school environments, the deleterious health impacts of environmental hazards may be greater for children. The unique physical and behavioral characteristics of children as well as the paucity of research, policy, and regulation with regard to school environments and children's health underscore the need to recognize and address school children as a particularly vulnerable population.
Children are not “little adults,” and, therefore, assessments of their exposures to, and outcomes resulting from, environmental toxicants using adult-based toxicological models are insufficient. Children breathe more, eat more, and drink more per pound of body weight than adults, increasing their risk of exposures. Their behaviors also expose them to more possible contaminants (e.g., hand-to-mouth behaviors, more time spent on the ground), and they cannot always identify and protect themselves against hazards (Guzelian, 1992; National Research Council, 1993).
Not only are children generally exposed to toxins at higher levels than adults, they may also absorb the toxins more readily than adults, placing them at even greater risk of harm. The efficiency of detoxification and elimination of toxins from the body may differ in children and adults. For example, young children may lack sufficient amounts of a key enzyme needed to metabolize and excrete a particular contaminant quickly, resulting in longer residency time of the contaminant in the body, leading potentially to greater toxicity and harm.
Children's organ systems continue developing through early childhood and are, thus, more vulnerable to adverse effect. Longer exposures to some toxins, such as those experienced since early childhood, leads to greater body burdens, with potentially more detrimental health outcomes. Those with existing disabilities may be more vulnerable, both with regard to exposure and absorption, and, thus, at even greater risk.
Policy and Regulation
Public sector employees (including teachers and others working within the public school system) in 25 states are protected from environmental and occupational hazards through state-adopted, Occupational Safety and Health Administration (OSHA)–approved standards. All but 4 of these states also provide protection to private sector employees, such as private school staff and administrators (Healthy Schools Network, 2005). Injured workers may also be eligible for, and receive, worker's compensation, sick leave, union support, and access to U.S. Department of Health and Human Services–funded occupational health clinics; they may also be able to switch their job locations. Thus, there exists protection for some of the adults employed in schools in the United States.
However, OSHA standards do not exist for any of the children attending these schools who are exposed to the same environmental hazards and are more vulnerable to their effects. In addition, chemical regulations under the Toxic Substances Control Act (TSCA) of 1976 in the U.S. do not guarantee adequate protection to children because they are based upon risk assessment models derived from adult populations and other inherently limited assumptions (Environmental Working Group [EWG], 2005).
Whereas the health effects of some contaminants, such as lead, tobacco, and asbestos, have been well studied, barely any of the approximately 80,000 chemicals inventoried by the TSCA have been fully tested for their impacts on human health (U.S. General Accounting Office, 2005). In fact, only 7% of the 2,863 most commonly used chemicals have undergone complete toxicological testing, and few of these have been studied for neurodevelopmental effects (EPA, 1998).
Research of children's environmental health issues at school is either minimal or nonexistent. In fact a seemingly noncontagious outbreak of rashes in 2001–2002, which affected approximately 1,000 children in 27 states, could not be meaningfully investigated due to the lack of baseline data of children's environmental health measures at schools (Healthy Schools Network, 2005).
The National Institute for Occupational Safety and Health (NIOSH) performed a workplace evaluation of a school near “ground zero” in New York City and found evidence of new-onset diseases among school staff. However, no agency offered a similar service for students, including children with special needs, in the dust-contaminated school (Bartlett & Petrarca, 2002). Furthermore, had any investigations been conducted, meaningful assessment would have been difficult due to the lack of any baseline data on students' health.
A NIOSH Healthy Hazard Evaluation (HHE) evaluates worker health and safety on site based on previous and current individual medical conditions. The same type of evaluation could have been done for school children but was not, thus depriving children (who outnumber adults in schools), their families, schools, IEO sciences, and NIOSH of important information. Children are the work product, or “output,” of schools, so not having any assessment of them erodes the educational mission.
Specific School Facilities Issues
Some environmental concerns, such as the prevention of urban sprawl, the creation of walkable and bikable communities, the need for safe routes to school, and the selection of a locale conducive to high-performing schools, are often considered when choosing a school site; however, the presence of on- or off-site sources of pollution are usually not considered. This is mainly due to considerations of land cost and availability (CHEJ, 2005). School districts seek out inexpensive land due to declining school budgets and rising, unfunded mandates, such as the No Child Left Behind Act (legislation enacted in 2002 that ties federal funding for schools to states' performances in standards-based assessments). Contaminated land is inexpensive because it is unsuitable for housing and most types of businesses.
Availability of land is another factor in site selection. School districts in rural areas look to site schools on inexpensive, unused agricultural land, which is often contaminated with pesticides, whereas urban school districts, limited in their siting choices due to the shortage of undeveloped land, often turn to sites on or near abandoned landfills or abandoned industrial sites, such as brownfields, or near heavily polluting industries (CHEJ, 2005). Furthermore, urban school districts, motivated to save money or to devote greater percentages of their budgets to hiring highly qualified teachers and improving schools' technology and curriculum, may be unwilling to invest in proper clean up of contaminated sites. There are 1,100 public schools, and over 600,000 students attending public schools, within half a mile of contaminated sites (CHEJ, 2005). This issue directly affects children's health, especially low-income and non-White children, who may have less access to health care and who have higher rates of asthma and lead poisoning (CHEJ, 2005).
According to a 50-state siting laws survey detailed in a 2005 report entitled Building Safe Schools: Invisible Threats, Visible Actions, only 10 states have laws that prohibit the siting of a school on or near sources of pollution or other environmental hazards (CHEJ, 2005). These hazards include sites affected by air, motor vehicle, and rail traffic; sites near utility transmission lines; sites impacted by air and noise pollution; sites where hazardous or solid waste was disposed; and sites especially vulnerable to natural hazards, such as flooding or earthquakes.
The report indicated that only 6 states require environmental investigation of potential school sites, such as the preparation of Phase I or Phase II environmental assessments or environmental impact statements for school projects. A Phase I environmental assessment is a cursory evaluation of the site, in which surveyors check for obvious signs of hazards, such as those that can be seen or smelled. Phase II assessments would be based on the findings of a Phase I assessment and would involve actual testing of site media (e.g., soil, water, air). Environmental impact statements or reports document the positive and negative environmental effects of a proposed action, such as the building of a school, and cite alternative actions. Twelve states require public notice or public meetings about proposed school sites, and 8 states require or authorize the creation of school siting advisory committees.
The report also revealed that 20 states have no laws that either prohibit or restrict the siting of a school on or near man-made or naturally occurring environmental hazards and that 24 states do not require school districts to investigate potential school sites for the presence of pollutants or other environmental hazards or to assess environmental impacts associated with potential school sites.
Potential toxicants at contaminated sites include heavy metals, such as lead, arsenic, cadmium, and mercury; organic chemicals, such as benzene and toluene (commonly from underground storage tanks and gasoline contamination); chlorophenols, benzo[a]pyrene, and naphthalene from creosote at wood treatment operations; polychlorinated biphenyls, which often at sites where electrical equipment has been in use; and many more (CHEJ, 2005).
Many of the heavy metals, most notably lead and mercury, are known neurotoxicants. Mercury impairs brain development and reduces IQ (U.S. Agency for Toxic Substances and Disease Registry [ATSDR], 1999). Lead reduces IQ levels, leads to cognitive and attention deficits, and is linked to oppositional behaviors, aggression, and violence (ATSDR, 2007). Benzene and toluene also adversely affect the central nervous system. They are also both associated with adverse reproductive effects, and benzene, in particular, is associated with leukemia (ATSDR, 2000, 2007). PCBs are also suspected of impairing cognitive functioning in children, although more studies on its health effects are needed (ATSDR, 2000).
There is a compelling need for comprehensive school siting laws that would restrict siting on or near sources of environmental hazards and require thorough investigation and assessment of hazards on potential school sites or impacts to future users of sites; proper clean up, remediation, and monitoring of contaminated sites; and public involvement in siting decisions. An example of a thorough siting process is illustrated in Figure 1.
A public education component is also critical to a comprehensive siting process. The virtual absence of state laws and federal guidelines on school siting is not common knowledge. In addition, chemical contamination clean-up programs are complicated and often not well understood by the general population. Thus, parents and school communities may often be unaware of on-site contamination, demonstrating the need for a strong educational element as part of the process.
Material safety data sheets written by a cleaning product's manufacturer do not always provide complete information on the health hazards of the product and are not required at all for retail products (Kolp, Williams, & Burtan, 1995). Conventional cleaning products may contain carcinogens (cancer-causing agents) and ingredients that affect the central nervous system; the respiratory system, such as asthmagens; and development and reproduction (Grandjean & Landrigan, 2006; Main et al., 2006; Petsonk, 2002; Rumchev, Spickett, Bulsara, Phillips, & Stick, 2004; Swan et al., 2005'; U.S. National Toxicology Program, 2000). Ingredients commonly found in cleaners, such as aliphatic polyamines, ammonia, hydrochloric acid, and monoethanolamine, have been linked with respiratory disease, as have some ingredients found in disinfectants such as chloramine-T and quaternary ammonium compounds, including benzalkonium chloride (Association of Occupational and Environmental Clinics [AOEC], 2000; Purohit et al., 2000; Savonius, Keskinen, Tupperainen, & Kanerva, 1994). Some fragrances and volatile organic compounds (VOCs) found in certain cleaning products also are associated with respiratory illness (AOEC, 2000; Rumchev, Spickett, Bulsara, Phillips, & Stick, 2004).
Endocrine-disrupting chemicals (EDCs) are commonly found in cleaning products and can be harmful to the human body in very small doses. The endocrine system regulates growth, development, metabolism, puberty, and many of the functions of all other body systems via the release of specific chemical messengers called hormones. Hormones attach to receptors on cell surfaces, carrying information into the cells and triggering certain essential actions. EDCs, also termed hormone-disrupting chemicals, can either block hormones from attaching to their proper cell receptors or mimic hormones and bind with the cells themselves; either way, important bodily processes are impacted, and adverse health outcomes may ensue. The following EDCs are common ingredients in cleaning products: dibutyl phthalate and diethyl phthalate, found in floor care products and fragrances, and alkylphenol ethoxylates, found in all-purpose cleaners and specialty cleaners (AOEC, 2000; Main et al., 2006; Swan et al., 2005). Table 1 lists common conventional cleaning chemicals and some less toxic substitutes.
In 2005 the Chicago public schools adopted a green cleaning policy (Environmental Law Institute [ELI], 2007), New York state issued an executive order mandating the use of environmentally preferred cleaning products (Executive Order 134), and the New York state legislature passed supporting legislation for all K–12 public and private schools (ELI, 2007).
Illinois passed similar legislation in 2007, and a movement grew in New England to follow suit (ELI, 2007). As of spring 2009, 17 states had adopted green cleaning procurement policies (Balek, 2009). In addition, nationwide, many school districts have begun to embrace, or have already adopted, green cleaning regimens, even in the absence of state mandates.
An effective and comprehensive green cleaning program focuses not only on reducing the use of toxic chemical cleaners but calls for the use of more efficient equipment and the implementation of proper training protocols for the cleaning staff. Third-party–certified cleaning chemicals, both for everyday use and for specialty cleaning uses (e.g., floor sealers and finishes), are required. A product must meet strict, and continually updated, human and environmental health criteria throughout its lifecycle to achieve certification. In a green cleaning program, the majority of everyday cleaning can be accomplished with just one third-party–certified, all-purpose concentrate, greatly reducing the number of different chemicals in use. Environmentally preferable disinfectants, graffiti removers, mineral build-up removers, and white board cleaners and markers are also available to replace their conventional equivalent. Investment in equipment such as HEPA-filter vacuum cleaners, high-filtration floor care equipment, microfiber cloths and mops, and multilevel, scraper walk-off mats, greatly improves indoor air quality. Green cleaning custodial training programs ideally include instruction on best practices, proper equipment operation, and the use of the new certified cleaning products, as well as information on bloodborne pathogens and chemical right-to-know; these programs would be provided in a multilingual format where necessary.
Reducing the use of antimicrobials is another important goal of green cleaning programs. The overuse of antibacterial soaps, wipes, and washes may be creating antibiotic-resistant strains of bacteria (McDonnell & Russell, 1999). Conventional hand soaps can be replaced with third-party–certified and nonanti-bacterial soaps. Staff should be trained to clean prior to disinfecting and to use disinfectants in high-risk areas only, such as those areas required by regulations and those where body fluids may be present. Detergent and water can remove most microbes, and sanitizers may be appropriate for certain touch points, rather than disinfectants.
Schools planning to implement a green cleaning program need only invite their favored vendor to present a free demonstration of certified green cleaning products on real dirt to custodial staff and then initiate a pilot project by selecting products and practices to phase in, based on the unique needs of the site. For schools that want to assess the benefits of adopting a green cleaning program, an evaluation of the current products, equipment, and methods used on site should be conducted, and baseline measurements, such as the number of student visits to the nurse's office, should be obtained. Schools may also elect to establish an environmental health and safety committee to educate staff other than custodians and to monitor and reward success. Ideally, schools would adopt policy that would endure staff and administrative turnover. However, it is most important that schools understand how easy it is to begin a green cleaning program immediately.
The school environment presents an agreeable habitat for a number of various pests. Meals and snacks are served and eaten within school facilities, and moisture and nesting areas abound. Pests may also find suitable nutrients and habitat among books and other educational materials present within schools (Healthy Schools Network, 2006). Hazards associated with pests include the spread of diseases from flies, cockroaches, mice, and rats; allergies and asthma attacks triggered by cockroaches and mice; and allergic reactions to some insect bites or stings (EPA, 2009a). Structural damage from termite and mice activity may also present physical hazards to schoolbuilding occupants (EPA, 2009a). However, conventional pest control methods may introduce serious hazards of their own.
Routine pesticide application is often the primary means of pest prevention and control in U.S. schools, and herbicides are used on school grounds to control weeds. Herbicides and fungicides are formulated to kill certain plants and fungi, and insecticides and rodenticides are often neurotoxins designed to kill certain animal species via enzyme system disruption or cell membrane damage (EPA, 2009b).
These lethal compounds are potentially toxic to children, and adults. Indeed, pesticides registered with the EPA are not guaranteed to be safe for human health (Landrigan, Needleman, & Landrigan, 2002). Levels of the enzyme critical in detoxifying organophosphorous (OP) pesticides, in particular, and in protecting against oxidative stress remain low in children through at least Age 7 (Huen et al., 2009). Thus, this window of vulnerability to OPs includes school-aged children as well as infants, necessitating the implementation of safer pest management practices in schools. Regulatory authorities use a retroactive, “proof-of-harm” approach to pesticide regulation rather than taking a more precautionary tactic. Many older pesticides have not been thoroughly tested by today's standards and are still commonly used, despite the complete testing of each compound taking at least 10 years (Purdue University Cooperative Extension Service [PUCES], 2001). Furthermore, most pesticides in use today have not been tested specifically for their health effects on children (Landrigan, Needleman, & Landrigan, 2002).
Recent toxicological studies found that many pesticides harm the developing brain and nervous system. Some pesticides act as hormone disruptors, resulting in impaired development and functioning, and many herbicides are known, probable, or suspected carcinogens (Landrigan, Needleman, & Landrigan, 2002). Acute human health problems associated with pesticide exposure include eye and skin irritations, nausea, dizziness, breathing difficulties, upper respiratory infections, systemic manifestations, and even seizures and pulmonary edema in high-severity cases (Alarcon et al., 2005; Californians for Pesticide Reform, 2003; EPA, 1999). Long-term exposure to some pesticides has also been associated with chronic health problems, such as childhood cancers; respiratory diseases, such as asthma; abnormal brain development; and developmental and behavioral delays and disorders (Guillette, Meza, Aquilar, Soto, & Garcia, 1998; Lizardi, O'Rourke, & Morris, 2008; Rudant et al., 2007; Salam, Li, Langholz, & Gilliland, 2004; Weiss, Amler, & Amler, 2004).
Although no federal regulations exist for pesticide use in schools, the EPA recommends that schools use integrated pest management (IPM) practices to reduce the risk of pesticide exposure to children. IPM is a safer and usually less costly option for effective pest management within schools, although it does not eliminate use of pesticides altogether. A school IPM program takes advantage of all pest management strategies, including the judicious and careful use of pesticides when necessary. However, a properly implemented program focuses on implementing preventative measures and least toxic solutions, such as strategies to reduce sources of food, water, and shelter for pests within school buildings and grounds.
Proper school IPM practices include the following: vegetation, shrubs, and wood mulch are kept at least 1 foot away from structures; cracks and crevices in walls, floors, and pavement are either sealed or eliminated; lockers and desks are emptied and thoroughly cleaned at least twice a year; all food-contaminated dishes, utensils, and surfaces are cleaned by the end of each day; garbage cans and dumpsters are cleaned regularly; litter is collected and disposed of properly at least once a week; fertilizers are applied several times throughout the year rather than one heavy application; the problem or pest is identified prior to taking action; and spot treatments, rather than area-wide applications, of pesticides are used when pesticides are needed (EPA, 2009a). Pesticides can travel long distances and have been found as far as 50 miles away from the point of application (Californians for Pesticide Reform, 2003). Thus, reduction of pesticide drift, particularly for schools near agricultural fields, is also critical, and pesticide-spray buffer zones should be established around school buildings. Last, schools should strive to educate their school communities about pesticides and IPM practices and notify and provide re-entry recommendations when pesticides are used (NIOSH, 2007).
School facilities in the United States are densely occupied, understaffed, underfunded, and often designed and built by low bidders, without any, or minimal, oversight. Maintenance budgets are often the first to be reduced when budgets shrink. In addition to poor availability of school sites and the lack of research and policy regulation, these realities pose considerable unaddressed health hazards to schoolchildren across the country.
Siting committees need to establish environmentally sound protocol for selecting new school sites, and new schools need help to improve the design and construction of the facility. Existing schools should establish an environmental health committee to report on facility conditions and recommend improvements; to provide advance notice to parents, staff, and the community of school construction projects and the public plan to protect occupants; to physically separate construction from occupants and air out new areas prior to reoccupancy; to practice nontoxic pest control, such as IPM practices; to adopt green cleaning practices; and to inventory and clean out “legacy” stored chemicals.
Research, such as the National Children's Study, funded and led primarily by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, should capture exposures in daycare settings and schools. Health providers, advised by the EPA, should develop a common way to assess these exposures. Advocates should insist that congress supports and federal agencies create a coordinated strategy for children's health at school.
Funded by the John Merck Fund.