- 1 Food safety
- 2 Key facts
- 3 Major foodborne illnesses and causes
- 4 Chemicals:
- 5 The burden of foodborne diseases
- 6 The evolving world and food safety
- 7 Food safety: a public health priority
- 8 WHO response
- 9 Classification & Distribution
- 10 Life History & Ecology
- 11 Physical Features
- 12 Adults:
- 13 Immatures:
- 14 Economic Importance
- 15 Major Families
- 16 Bug Bytes
- 17 US EPA
- 18 Health Effects Notebook
- 19 Introduction
- 20 Related Links
- 21 General Information
- 22 Fact Sheet Organization
- 23 Graph
- 24 Data Sources
- Access to sufficient amounts of safe and nutritious food is key to sustaining life and promoting good health.
- Unsafe food containing harmful bacteria, viruses, parasites or chemical substances, causes more than 200 diseases – ranging from diarrhoea to cancers.
- An estimated 600 million – almost 1 in 10 people in the world – fall ill after eating contaminated food and 420 000 die every year, resulting in the loss of 33 million healthy life years (DALYs).
- Children under 5 years of age carry 40% of the foodborne disease burden, with 125 000 deaths every year.
- Diarrhoeal diseases are the most common illnesses resulting from the consumption of contaminated food, causing 550 million people to fall ill and 230 000 deaths every year.
- Food safety, nutrition and food security are inextricably linked. Unsafe food creates a vicious cycle of disease and malnutrition, particularly affecting infants, young children, elderly and the sick.
- Foodborne diseases impede socioeconomic development by straining health care systems, and harming national economies, tourism and trade.
- Food supply chains now cross multiple national borders. Good collaboration between governments, producers and consumers helps ensure food safety.
Major foodborne illnesses and causes
Foodborne illnesses are usually infectious or toxic in nature and caused by bacteria, viruses, parasites or chemical substances entering the body through contaminated food or water.
Foodborne pathogens can cause severe diarrhoea or debilitating infections including meningitis.
Chemical contamination can lead to acute poisoning or long-term diseases, such as cancer. Foodborne diseases may lead to long-lasting disability and death. Examples of unsafe food include uncooked foods of animal origin, fruits and vegetables contaminated with faeces, and raw shellfish containing marine biotoxins.
- Salmonella, Campylobacter, and Enterohaemorrhagic Escherichia coli are among the most common foodborne pathogens that affect millions of people annually – sometimes with severe and fatal outcomes. Symptoms are fever, headache, nausea, vomiting, abdominal pain and diarrhoea. Examples of foods involved in outbreaks of salmonellosis are eggs, poultry and other products of animal origin. Foodborne cases with Campylobacter are mainly caused by raw milk, raw or undercooked poultry and drinking water. Enterohaemorrhagic Escherichia coli is associated with unpasteurized milk, undercooked meat and fresh fruits and vegetables.
- Listeria infection leads to unplanned abortions in pregnant women or death of newborn babies. Although disease occurrence is relatively low, listeria’s severe and sometimes fatal health consequences, particularly among infants, children and the elderly, count them among the most serious foodborne infections. Listeria is found in unpasteurised dairy products and various ready-to-eat foods and can grow at refrigeration temperatures.
- Vibrio cholerae infects people through contaminated water or food. Symptoms include abdominal pain, vomiting and profuse watery diarrhoea, which may lead to severe dehydration and possibly death. Rice, vegetables, millet gruel and various types of seafood have been implicated in cholera outbreaks.
Antimicrobials, such as antibiotics, are essential to treat infections caused by bacteria. However, their overuse and misuse in veterinary and human medicine has been linked to the emergence and spread of resistant bacteria, rendering the treatment of infectious diseases ineffective in animals and humans. Resistant bacteria enter the food chain through the animals (e.g. Salmonella through chickens). Antimicrobial resistance is one of the main threats to modern medicine.
Norovirus infections are characterized by nausea, explosive vomiting, watery diarrhoea and abdominal pain. Hepatitis A virus can cause long-lasting liver disease and spreads typically through raw or undercooked seafood or contaminated raw produce. Infected food handlers are often the source of food contamination.
Some parasites, such as fish-borne trematodes, are only transmitted through food. Others, for example tapeworms like Echinococcus spp, or Taenia solium, may infect people through food or direct contact with animals. Other parasites, such as Ascaris, Cryptosporidium, Entamoeba histolytica or Giardia, enter the food chain via water or soil and can contaminate fresh produce.
Prions, infectious agents composed of protein, are unique in that they are associated with specific forms of neurodegenerative disease. Bovine spongiform encephalopathy (BSE, or «mad cow disease») is a prion disease in cattle, associated with the variant Creutzfeldt-Jakob Disease (vCJD) in humans. Consuming bovine products containing specified risk material, e.g. brain tissue, is the most likely route of transmission of the prion agent to humans.
Of most concern for health are naturally occurring toxins and environmental pollutants.
- Naturally occurring toxins include mycotoxins, marine biotoxins, cyanogenic glycosides and toxins occurring in poisonous mushrooms. Staple foods like corn or cereals can contain high levels of mycotoxins, such as aflatoxin and ochratoxin, produced by mould on grain. A long-term exposure can affect the immune system and normal development, or cause cancer.
- Persistent organic pollutants (POPs) are compounds that accumulate in the environment and human body. Known examples are dioxins and polychlorinated biphenyls (PCBs), which are unwanted by-products of industrial processes and waste incineration. They are found worldwide in the environment and accumulate in animal food chains. Dioxins are highly toxic and can cause reproductive and developmental problems, damage the immune system, interfere with hormones and cause cancer.
- Heavy metalssuch as lead, cadmium and mercury cause neurological and kidney damage. Contamination by heavy metal in food occurs mainly through pollution of air, water and soil.
The burden of foodborne diseases
The burden of foodborne diseases to public health and welfare and to economy has often been underestimated due to underreporting and difficulty to establish causal relationships between food contamination and resulting illness or death.
The 2015 WHO report on the estimates of the global burden of foodborne diseases presented the first-ever estimates of disease burden caused by 31 foodborne agents (bacteria, viruses, parasites, toxins and chemicals) at global and regional level.
The evolving world and food safety
Safe food supplies support national economies, trade and tourism, contribute to food and nutrition security, and underpin sustainable development.
Urbanization and changes in consumer habits, including travel, have increased the number of people buying and eating food prepared in public places. Globalization has triggered growing consumer demand for a wider variety of foods, resulting in an increasingly complex and longer global food chain.
As the world’s population grows, the intensification and industrialization of agriculture and animal production to meet increasing demand for food creates both opportunities and challenges for food safety. Climate change is also predicted to impact food safety, where temperature changes modify food safety risks associated with food production, storage and distribution.
These challenges put greater responsibility on food producers and handlers to ensure food safety. Local incidents can quickly evolve into international emergencies due to the speed and range of product distribution. Serious foodborne disease outbreaks have occurred on every continent in the past decade, often amplified by globalized trade.
Examples include the contamination of infant formula with melamine in 2008 (affecting 300 000 infants and young children, 6 of whom died, in China alone), and the 2011 Enterohaemorrhagic Escherichia coli outbreak in Germany linked to contaminated fenugreek sprouts, where cases were reported in 8 countries in Europe and North America, leading to 53 deaths and significant economic losses.
Food safety: a public health priority
Unsafe food poses global health threats, endangering everyone. Infants, young children, pregnant women, the elderly and those with an underlying illness are particularly vulnerable. Every year 220 million children contract diarrhoeal diseases and 96 000 die.
Unsafe food creates a vicious cycle of diarrhoea and malnutrition, threatening the nutritional status of the most vulnerable. Where food supplies are insecure, people tend to shift to less healthy diets and consume more “unsafe foods” – in which chemical, microbiological and other hazards pose health risks.
The Second International Conference on Nutrition (ICN2), held in Rome in November 2014, reiterated the importance of food safety in achieving better human nutrition through healthy nutritious diets. Improving food safety is thus a key in achieving Sustainable Development Goals. Governments should make food safety a public health priority, as they play a pivotal role in developing policies and regulatory frameworks, establishing and implementing effective food safety systems that ensure that food producers and suppliers along the whole food chain operate responsibly and supply safe food to consumers.
Food can become contaminated at any point of production and distribution, and the primary responsibility lies with food producers. Yet a large proportion of foodborne disease incidents are caused by foods improperly prepared or mishandled at home, in food service establishments or markets. Not all food handlers and consumers understand the roles they must play, such as adopting basic hygienic practices when buying, selling and preparing food to protect their health and that of the wider community.
Everyone can contribute to making food safe. Here are some examples of effective actions:
- build and maintain adequate food systems and infrastructures (e.g. laboratories) to respond to and manage food safety risks along the entire food chain, including during emergencies;
- foster multi-sectoral collaboration among public health, animal health, agriculture and other sectors for better communication and joint action;
- integrate food safety into broader food policies and programmes (e.g. nutrition and food security);
- think globally and act locally to ensure the food produce domestically be safe internationally.
Food handlers and consumers can:
- know the food they use (read labels on food package, make an informed choice, become familiar with common food hazards);
- handle and prepare food safely, practicing the WHO Five Keys to Safer Food at home, or when selling at restaurants or at local markets;
- grow fruits and vegetables using the WHO Five Keys to Growing Safer Fruits and Vegetables to decrease microbial contamination.
WHO aims to facilitate global prevention, detection and response to public health threats associated with unsafe food. Ensuring consumer trust in their authorities, and confidence in the safe food supply, is an outcome that WHO works to achieve.
To do this, WHO helps Member States build capacity to prevent, detect and manage foodborne risks by:
- providing independent scientific assessments on microbiological and chemical hazards that form the basis for international food standards, guidelines and recommendations, known as the Codex Alimentarius, to ensure food is safe wherever it originates;
- assessing the safety of new technologies used in food production, such as genetic modification and nanotechnology;
- helping improve national food systems and legal frameworks, and implement adequate infrastructure to manage food safety risks. The International Food Safety Authorities Network (INFOSAN) was developed by WHO and the UN Food and Agriculture Organization (FAO) to rapidly share information during food safety emergencies;
- promoting safe food handling through systematic disease prevention and awareness programmes, through the WHO Five Keys to Safer Food message and training materials; and
- advocating for food safety as an important component of health security and for integrating food safety into national policies and programmes in line with the International Health Regulations (IHR — 2005).
WHO works closely with FAO, the World Organization for Animal Health (OIE) and other international organizations to ensure food safety along the entire food chain from production to consumption.
Classification & Distribution
- incomplete development (egg, nymph, adult)
- closely related to Thysanoptera and Psocoptera
Distribution: Abundant worldwide. Found in most terrestrial and freshwater habitats.
Life History & Ecology
Members of the suborder Heteroptera are known as «true bugs». They have very distinctive front wings, called hemelytra, in which the basal half is leathery and the apical half is membranous. At rest, these wings cross over one another to lie flat along the insect’s back. These insects also have elongate, piercing-sucking mouthparts which arise from the ventral (hypognathous) or anterior (prognathous) part of the head capsule. The mandibles and maxillae are long and thread-like, interlocking with one another to form a flexible feeding tube (proboscis) that is no more than 0.1 mm in diameter yet contains both a food channel and a salivary channel. These stylets are enclosed within a protective sheath (the labium) that shortens or retracts during feeding.
The Heteroptera include a diverse assemblage of insects that have become adapted to a broad range of habitats — terrestrial, aquatic and semi-aquatic. Terrestrial species are often associated with plants. They feed in vascular tissues or on the nutrients stored within seeds. Other species live as scavengers in the soil or underground in caves or ant nests. Still others are predators on a variety of small arthropods. A few species even feed on the blood of vertebrates. Bed bugs, and other members of the family Cimicidae, live exclusively as ectoparasites on birds and mammals (including humans). Aquatic Heteroptera can be found on the surface of both fresh and salt water, near shorelines, or beneath the water surface in nearly all freshwater habitats. With only a few exceptions, these insects are predators of other aquatic organisms.
- Antennae slender with 4-5 segments
- Proboscis 3-4 segmented, arising from front of head and curving below body when not in use
- Pronotum usually large, trapezoidal or rounded
- Triangular scutellum present behind pronotum
- Front wings with basal half leathery and apical half membranous (hemelytra). Wings lie flat on the back at rest, forming an «X».
- Tarsi 2- or 3-segmented
- Structurally similar to adults
- Always lacking wings
Plant feeding bugs are important pests of many crop plants. They may cause localized injury to plant tissues, they may weaken plants by removing sap, and they may also transmit plant pathogens. Predatory species of Heteroptera are generally regarded as beneficial insects, but those that feed on blood may transmit human diseases. Chagas disease, for example, is transmitted to humans by conenose bugs (genus Triatoma, family Reduviidae). Although bed bugs (family Cimicidae) can inflict annoying bites, there is little evidence that they regularly transmit any human or animal pathogen.
The three largest families of Heteroptera are:
- Miridae (Plant Bugs) — Most species feed on plants, but some are predaceous. This family includes numerous pests such as the tarnished plant bug (Lygus lineolaris).
- Lygaeidae (Seed Bugs) — Most species are seed feeders, a few are predatory. This family includes the chinch bug, Blissus leucopterus a pest of small grains, and the bigeyed bug, Geocoris bullatis, a beneficial predator.
- Pentatomidae (Stink Bugs) — Shield-shaped body with large, triangular scutellum. Most species are herbivores, some are predators. All have scent glands which can produce an unpleasant odor.
Other families of terrestrial herbivores include:
- Tingidae (lace bugs)
- Coreidae (squash bugs and leaffooted bugs)
- Alydidae (broadheaded bugs)
- Rhopalidae (scentless plant bugs)
- Berytidae (stilt bugs)
Other families of terrestrial predators include:
- Reduviidae (assassin bugs)
- Phymatidae (ambush bugs)
- Nabidae (damsel bugs)
- Anthocoridae (minute pirate bugs)
The major families of aquatic predators include:
- Two families of Heteroptera are ectoparasites. The Cimicidae (bed bugs) live on birds and mammals (including humans). The Polyctenidae (bat bugs) live on bats.
- Water striders in the genus Halobates (family Gerridae) are the only insects that are truly marine. They live on the surface of the Pacific Ocean.
- Unlike other insects, male bedbugs do not place their sperm directly in the female’s reproductive tract. Instead, they puncture her abdomen and inject the sperm into her body cavity. The sperm swim to the ovaries where they fertilize the eggs. This unusual type of reproductive behavior is appropriately known as «traumatic insemination».
- Some members of the family Largidae resemble ants. They live as social parasites in ant nests, mimicking the ants’ behavior to get food
© 2020 by John R. Meyer
Last Updated: 23 January 2020
Health Effects Notebook
The chemical fact sheets contained in this notebook provide a hazard summary for each of the hazardous air pollutants specified in the Clean Air Act Amendments of 1990. These brief summaries are intended to provide a quick reference for pertinent toxicity information and to indicate where more comprehensive and primary information can be found. This information is targeted to those concerned with toxic air pollutants at the State and local levels. The information in the fact sheets is summarized from U.S.Environmental Protection Agency (EPA) databases, and, where EPA data are lacking, information from other sources has been added for a more complete picture of possible toxicity concerns. The fact sheets should be used as one of many information sources for understanding a pollutant’s human health hazard potential. In the case of listed compound categories, one or more representative compounds have been selected for the fact sheet summary.
The fact sheets do not represent EPA policy on health hazards and they should not be construed as constituting an EPA judgment about a hazard where a judgment does not already exist. In addition, they cannot be cited or quoted as a primary source of EPA health hazard information.
We have developed separately a glossary of health, exposure, and risk assessment terms and the definitions of acronyms used in the graphs that accompany the fact sheets. Also available is a hazardous air pollutants’ Fact Sheet chemical name and CAS number cross reference file, which contains an alphabetical listing of all the chemicals and their most common synonyms contained in this Notebook.
This health effects notebook contains fact sheets on hazardous air pollutants. These chemicals include volatile organic chemicals, chemicals used as pesticides and herbicides, inorganic chemicals, and radionuclides. Many of these chemicals are used for a variety of purposes in the United States today. Other chemicals, although not in use today, were used extensively in the past and may still be found in the environment.
These fact sheets were developed based on available human and/or animal data. The human data consist primarily of epidemiological studies, which are studies that examine the incidence, distribution, and control of disease in the human population. The primary type of epidemiologic studies used in the development of these fact sheets were occupational studies, which examined the effects of a chemical on a group of workers over time. The animal data are from studies that experimentally exposed animals to chemicals to observe and measure toxicity and disease development. These studies include effects data related to acute (short-term) exposures, subchronic (medium-length) exposures, and chronic (long-term) exposures.
The primary sources of information used to develop the fact sheets are EPA’s Integrated Risk Information System (IRIS),(http://www.epa.gov/iris/index.html), a database that summarizes available toxicity data and contains EPA’s assessment of the data, and secondary sources, such as EPA’s Health Assessment Documents, and the Agency for Toxic Substances and Disease Registry (ATSDR) Toxicological Profiles(http://www.atsdr.cdc.gov/substances/index.asp). In addition, databases such as the Hazardous Substances Data Bank (HSDB), which contains summaries of peer-reviewed literature, and the Registry of Toxic Effects of Chemical Substances (RTECS), which lists toxic effects of chemicals and is not peer reviewed, may be used.
Each bulleted piece of information on the fact sheet contains one or more reference numbers after it which correspond to the numbered references at the end of each fact sheet. Complete reference information is provided in the reference section of each fact sheet.
When available, numerical data are presented in the fact sheets. The numerical data presented are primarily those numbers that are found in the IRIS database. IRIS numbers are EPA- verified values; i.e, they have been subjected to extensive review by EPA scientists and a consensus was reached on their validity. These numbers include the Oral Reference Dose (RfD) and the Inhalation Reference Concentration (RfC) (see the Chronic Effects section) and the risk specific concentration (see the Cancer Risk section). They additionally include Minimal Risk Levels (MRLs) developed by the Agency for Toxic Substances and Disease Registry (ATSDR) and Reference Exposure Levels (RELs) developed by the California Environmental Protection Agency. These additional numbers have been developed in similar manner as the IRIS reference values and subjected to the similar degree of review and consensus, which is reflected in their prioritizaton by the EPA Office of Air Quality Planning and Standards.
The quality and decisiveness of the knowledge base underlying each of the agents portrayed in the fact sheets vary according to the abundance or paucity of high-quality health science data. The strength or confidence in particular hazard conclusions or inferences similarly varies according to the amount and quality of data and also according to the inherent methodologic generated uncertainties that go along with health hazard assessment. The overall effect of these circumstances is that each agent has its unique combination of uncertainty elements that are not explicitly listed in the fact sheets. A responsible user of these fact sheets must appreciate the implications of the underlying uncertainties, which take on more or less meaning depending on how the fact sheets are used.
The fact sheets focus on the health effects of each chemical in humans and laboratory animals (mammals). No information is presented on the ecological effects of the chemicals in nonmammalian species.
Fact Sheet Organization
The fact sheets are organized as follows:
Chemical Name and CAS Number
The chemical name and Chemical Abstract Service (CAS) registry number given on the fact sheet are the same as that used in the list of 189 hazardous air pollutants in the Clean Air Act Amendments of 1990. For listed compound categories, CAS numbers for one or more representative compounds have been selected.
The hazard summary is an overview of the key information provided in the Health Hazard Information section of the fact sheet.
This section presents the major uses of the chemical in the United States today. In addition, past uses of the chemical may be summarized.
Sources and Potential Exposure
This section contains information on how the general public may be exposed to the chemical, e.g., through water, food, or air, as well as information on occupational exposure. In addition, this section tells which chemicals have been listed as pollutants of concern to EPA’s Great Waters Program and the reason for the listing. The purpose of the Great Waters Program is to evaluate the atmospheric deposition of air pollutants to the Great Lakes, Lake Champlain, Chesapeake Bay, and coastal waters. All of the pollutants of concern possess certain common characteristics, including persistence in the environment and the potential for long-distance transport.
Assessing Personal Exposure
This section describes the medical tests available to determine whether a person has been exposed to the chemical.
Health Hazard Information
This section summarizes the key toxicology information on the chemical, emphasizing the inhalation (air) route of exposure. If available, oral and dermal (skin) exposure data are also presented.
Information on effects reported from acute animal tests and/or acute human studies are presented in this section. Acute human studies may be controlled exposure studies or may consist of case reports from accidental poisonings or industrial accidents. All of these studies help to define the acute exposure levels at which effects are seen in humans.
Acute animal studies often consist of LD50 and LC50 tests, which present the median lethal dose (or concentration) to the animals. The results from these tests are divided into the toxicity categories as shown below.
|Type of Dose/Concentration||Extreme||High||Moderate||Low|
|Oral LD50||50 thru 500 mg/kg||>500 thru 5,000 mg/kg||>5,000 mg/kg|
|Dermal LD50||200 thru 2,000 mg/kg||>2000 thru 20,000 mg/kg||>20,000 mg/kg|
|Inhalation LC50||200 thru 2,000 mg/m3||>2,000 thru 20,000 mg/m3||>20,000 mg/m3|
Based on 40 CFR 156.62.
This section summarizes the major chronic noncarcinogenic effects seen from exposure to the chemical. Chronic animal studies usually range from 90 days’ to 2 years’ duration. Human studies investigating effects ranging from exposure of a few years to a lifetime are also included. In addition, subchronic studies may be included in this section. Subchronic studies are usually animal studies of several weeks’ to 90 days’ duration.
The Inhalation RfC (or MRL or REL) is presented in this section, with information on the critical effect and species upon which it is based. The RfC is an estimate (with uncertainty spanning perhaps an order of magnitude) of the daily exposure of a chemical to the human population by inhalation (including sensitive subpopulations) that is likely to be without deleterious effects during a lifetime of exposure. It is based on the available toxicological data, using uncertainty factors to account for data gaps such as experimental animal-to-human extrapolation and extrapolation to sensitive members of the population. The RfC is not a direct or absolute estimator of risk, but rather a reference point to gauge the potential effects. Exposures at or below the RfC are not likely to be associated with any adverse health effects. However, exceedance of the RfC does not imply that an adverse health effect would necessarily occur. As the amount and frequency of exposures exceeding the RfC increase, the probability that adverse effects may be observed in the human population also increases. If available, the oral RfD is also presented in this section. The RfD is the oral equivalent of the RfC.
EPA’s confidence in the RfC and/or RfD is also presented in this section. In the past, EPA ranked each RfC and RfD as either low, medium, or high in three areas: (1) confidence in the study on which the RfC or RfD was based; (2) confidence in the database; (3) overall confidence in the RfC or RfD. As available, all three rankings are presented in this section.
Reproductive and Developmental Effects
This section presents the results of reproductive and developmental studies on the effects of the chemical in animals and humans. Examples of female reproductive effects include reduced fertility, a decrease in the survival of offspring, and alterations in the reproductive cycle. Male reproductive effects include a decrease in sperm count or an increase in abnormal sperm morphology. Developmental effects are adverse effects on the developing organism that result from exposure prior to conception (either parent), during prenatal development, or postnatally to the time of sexual maturation. Examples include altered growth, death of the developing organism, and malformations or birth defects. Reproductive and developmental effects may be observed after short-term or long-term exposure to the chemical because some effects can be attributed to one-time or short-term exposures during a critical biological cycle.
The results of available cancer studies in animals and/or humans are presented in this section. In addition, the EPA weight of evidence characterization of the evidence with regard to the chemical’s potential to be carcinogenic to humans is included.
The cancer risk section also includes the inhalation unit risk for a chemical, which is the increased probability of a person developing cancer from breathing air containing a specified concentration of the chemical for a lifetime. The inhalation unit risk is derived using mathematical models that assume a nonthreshold approach; i.e., there is some risk of cancer occurring at any level of exposure. The methods used to derive these values result in an «upper bound» estimate; i.e., the true risk is unlikely to exceed this value and may be much lower. The lifetime risk-based concentration, an estimate of the chemical concentration for which a lifetime continuous exposure corresponds to a specified level of cancer risk, is also presented in this section. The risk-based concentrations corresponding to a one-in-a-million, one-in-a-hundred thousand, and one-in-ten thousand excess risk attributed to exposure to the chemical are presented. This means that EPA has estimated that, if an individual were to breathe air containing these concentrations of the chemical over his or her entire lifetime, that person would theoretically have no more than a one-in-a-million, one-in-a-hundred thousand, or one-in-ten thousand increased chance of developing cancer as a direct result of breathing air containing the chemical. The use of the risk-based concentration should include recognition of the weight-of-evidence.
This section provides the physical state (solid, liquid, or gas) of the chemical at ambient conditions, as well as solubility information and the odor threshold of the chemical (if available). The chemical formula, molecular weight, vapor pressure, and octanol/water partition coefficient are also provided in this section.
Following each fact sheet is a graph that visually presents the available toxicity or health risk numbers, showing the concentration (on a logarithmic scale). The numbers labeled as «toxicity and health risk» on the graph are LC50 and LD50 numbers, the RfC (or MRL or REL), RfD, lowest-observed-adverse-effect level (LOAEL) and no-observed-adverse-effect level (NOAEL), which are the basis for the RfC, MRL, REL RfD; lifetime risk-based concentrations developed based on cancer risk estimates cited in EPA’s IRIS (or California EPA). Relevant regulatory and advisory numbers are also included on the graph. Regulatory numbers consist of values that have been incorporated in government regulations, such as EPA and State air regulations or the Occupational Safety and Health Administration’s (OSHA’s) occupational standards. Advisory numbers are nonregulatory values that are provided by the Federal Government, State Government, or other groups as advice. Examples include EPA’s Health Advisories and the American Conference of Governmental and Industrial Hygienist’s (ACGIH’s) threshold limit values (TLVs). The graphs present health data for inhalation exposure only. For those chemicals that lack inhalation data, a graph on health data from oral exposure has been included.
The data sources relied on for each fact sheet are specified in the References section of each sheet.