There are relatively simple tests for radon gas. Radon test kits are commercially available. The short-term radon test kits used for screening purposes are inexpensive, in many cases free. Discounted test kits can be purchased online through The National Radon Program Services at Kansas State University or through state radon offices. Information about local radon zones and specific state contact information can be accessed through the EPA Map at https://www.epa.gov/radon/find-information-about-local-radon-zones-and-state-contact-information. The kit includes a collector that the user hangs in the lowest livable floor of the dwelling for 2 to 7 days. Charcoal canisters are another type of short-term radon test, and are designed to be used for 2 to 4 days. The user then sends the collector to a laboratory for analysis. Both devices are passive, meaning that they do not need power to function.

It should be noted that the accuracy of the residential radon test depends upon the lack of ventilation in the house when the sample is being obtained. Thus, the occupants will be instructed not to open windows, etc., for ventilation during the pendency of test, usually two days or more.

Long-term kits, taking collections for 3 months up to one year, are also available. An open-land test kit can test radon emissions from the land before construction begins. A Lucas cell is one type of long-term device. A Lucas cell is also an active device, or one that requires power to function. Active devices provide continuous monitoring, and some can report on the variation of radon and interference within the testing period. These tests usually require operation by trained testers and are often more expensive than passive testing. The National Radon Proficiency Program (NRPP) provides a list of radon measurement professionals.

Radon levels fluctuate naturally. An initial test might not be an accurate assessment of a home's average radon level. Transient weather can affect short term measurements. Therefore, a high result (over 4 pCi/L) justifies repeating the test before undertaking more expensive abatement projects. Measurements between 4 and 10 pCi/L warrant a long-term radon test. Measurements over 10 pCi/L warrant only another short-term test so that abatement measures are not unduly delayed. Purchasers of real estate are advised to delay or decline a purchase if the seller has not successfully abated radon to 4 pCi/L or less.

Since radon concentrations vary substantially from day to day, single grab-type measurements are generally not very useful, except as a means of identifying a potential problem area, and indicating a need for more sophisticated testing. The EPA recommends that an initial short-term test be performed in a closed building. An initial short-term test of 2 to 90 days allows residents to be informed quickly in case a home contains high levels of radon. Long-term tests provide a better estimate of the average annual radon level.

When exposure to a carcinogenic substance is suspected, the cause/effect relationship on any given case can never be ascertained. Lung cancer occurs spontaneously, and there is no difference between a "natural" cancer and another one caused by radon (or smoking). Furthermore, it takes years for a cancer to develop, so that determining the past exposure of a case is usually very approximative. The health effect of radon can only be demonstrated through theory and statistical observation.

The study design for epidemiological methods may be of three kinds:

- The best proofs come from observations of cohorts (predetermined populations with known exposures and exhaustive follow-up), such as those on miners, or on Hiroshima and Nagasaki survivors. Such studies are efficient, but very costly when the population needs to be a large one. Such studies can only be used when the effect is strong enough, hence, for high exposures.

- Alternate proofs are case-control studies (the environment factors of a "case" population is individually determined, and compared to that of a "control″ population, to see what the difference might have been, and which factors may be significant), like the ones that have been used to demonstrate the link between lung cancer and smoking. Such studies can identify key factors when the signal/noise ratio is strong enough, but are very sensitive to selection bias, and prone to the existence of confounding factors.

- Lastly, ecological studies may be used (where the global environment variables and their global effect on two different populations are compared). Such studies are "cheap and dirty": they can be easily conducted on very large populations (the whole USA, in Dr Cohen's study), but are prone to the existence of confounding factors, and exposed to the ecological fallacy problem.

Furthermore, theory and observation must confirm each other for a relationship to be accepted as fully proven. Even when a statistical link between factor and effect appears significant, it must be backed by a theoretical explanation; and a theory is not accepted as factual unless confirmed by observations.

A fiber cannot be identified or ruled out as asbestos, either using the naked eye or by simply looking at a fiber under a regular microscope. The most common methods of identifying asbestos fibers are by using polarized light microscopy (PLM) or transmission electron microscopy (TEM). PLM is less expensive, but TEM is more precise and can be used at lower concentrations of asbestos.

If asbestos abatement is performed, completion of the abatement is verified using visual confirmation and may also involve air sampling. Air samples are typically analyzed using phase contrast microscopy (PCM). PCM involves counting fibers on a filter using a microscope. Airborne occupational exposure limits for asbestos are based on using the PCM method.

The American Conference of Governmental Industrial Hygienists has a recommended Threshold Limit Value (TLV) for asbestos of 0.1 fibers/mL over an 8-hour shift. OSHA in the United States and occupational health and safety regulatory jurisdictions in Canada use 0.1 fibers/mL over an 8-hour shift as their exposure limits.

Pesticides exposure cannot be studied in placebo controlled trials as this would be unethical. A definitive cause effect relationship therefore cannot be established. Consistent evidence can and has been gathered through other study designs. The precautionary principle is thus frequently used in environmental law such that absolute proof is not required before efforts to decrease exposure to potential toxins are enacted.

The American Medical Association recommend limiting exposure to pesticides. They came to this conclusion due to the fact that surveillance systems currently in place are inadequate to determine problems related to exposure. The utility of applicator certification and public notification programs are also of unknown value in their ability to prevent adverse outcomes.

The current reference range for acceptable blood lead concentrations in healthy persons without excessive exposure to environmental sources of lead is less than 5 µg/dL for children. It was less than 25 µg/dL for adults. Previous to 2012 the value for children was 10 (µg/dl). The current biological exposure index (a level that should not be exceeded) for lead-exposed workers in the U.S. is 30 µg/dL in a random blood specimen.

In 2015, US HHS/CDC/NIOSH designated 5 µg/dL (five micrograms per deciliter) of whole blood, in a venous blood sample, as the reference blood lead level for adults. An elevated BLL is defined as a BLL ≥5 µg/dL. This case definition is used by the ABLES program, the Council of State and Territorial Epidemiologists (CSTE), and CDC’s National Notifiable Diseases Surveillance System (NNDSS). Previously (i.e. from 2009 until November 2015), the case definition for an elevated BLL was a BLL ≥10 µg/dL. The U.S. national BLL geometric mean among adults was 1.2 μg/dL in 2009–2010.

Blood lead concentrations in poisoning victims have ranged from 30->80 µg/dL in children exposed to lead paint in older houses, 77–104 µg/dL in persons working with pottery glazes, 90–137 µg/dL in individuals consuming contaminated herbal medicines, 109–139 µg/dL in indoor shooting range instructors and as high as 330 µg/dL in those drinking fruit juices from glazed earthenware containers.

Many studies have examined the effects of pesticide exposure on the risk of cancer. Associations have been found with: leukemia, lymphoma, brain, kidney, breast, prostate, pancreas, liver, lung, and skin cancers. This increased risk occurs with both residential and occupational exposures. Increased rates of cancer have been found among farm workers who apply these chemicals. A mother's occupational exposure to pesticides during pregnancy is associated with an increases in her child's risk of leukemia, Wilms' tumor, and brain cancer. Exposure to insecticides within the home and herbicides outside is associated with blood cancers in children.

A number of measurements exist to assess exposure and early biological effects for organophosphate poisoning. Measurements of OP metabolites in both the blood and urine can be used to determine if a person has been exposed to organophosphates. Specifically in the blood, metabolites of cholinesterases, such as butyrylcholinesterase (BuChE) activity in plasma, neuropathy target esterase (NTE) in lymphocytes, and of acetylcholinesterase (AChE) activity in red blood cells. Due to both AChE and BuChE being the main targets of organophosphates, their measurement is widely used as an indication of an exposure to an OP. The main restriction on this type of diagnosis is that depending on the OP the degree to which either AChE or BuChE are inhibited differs; therefore, measure of metabolites in blood and urine do not specify for a certain OP. However, for fast initial screening, determining AChE and BuChE activity in the blood are the most widely used procedures for confirming a diagnosis of OP poisoning. The most widely used portable testing device is the Test-mate ChE field test, which can be used to determine levels of Red Blood Cells (RBC), AChE and plasma (pseudo) cholinesterase (PChE) in the blood in about four minutes. This test has been shown to be just as effective as a regular laboratory test and because of this, the portable ChE field test is frequently used by people who work with pesticides on a daily basis.

Education and counselling by physicians of children and adolescents has been found to be effective in decreasing the risk of tobacco use.

Diseases commonly associated with asbestos include:

- Asbestosis: Progressive fibrosis of the lungs of varying severity, progressing to bilateral fibrosis, honeycombing of the lungs on radiological view with symptoms including rales and wheezing. Individuals who have been exposed to asbestos via home, environment, work should notify their doctors about exposure history.

- Asbestos warts: caused when the sharp fibers lodge in the skin and are overgrown causing benign callus-like growths.

- Pleural plaques: discrete fibrous or partially calcified thickened area which can be seen on X-rays of individuals exposed to asbestos. Although pleural plaques are themselves asymptomatic, in some patients this develops into pleural thickening.

- Diffuse pleural thickening: similar to above and can sometimes be associated with asbestosis. Usually no symptoms shown but if exposure is extensive, it can cause lung impairment.

- Pneumothorax: Some reports have also linked the condition of pneumothorax to asbestos related diseases.

It is important to consult a doctor, particularly if the following symptoms develop: shortness of breath, wheezing or hoarseness, persistent cough that worsens over time, blood in fluid coughed up, pain or tightening in chest, difficulty swallowing, swelling of neck or face, decreased appetite, weight loss, fatigue or anemia.

Dipping tobacco, commonly referred to as snuff, is also put in the mouth, but it is a flavored powder. it is placed between the cheek and gum. Dipping tobacco doesn't need to be chewed for the nicotine to be absorbed into your body. First-time users of these products often become nauseated and dizzy. Long-term effects include bad breath, yellowed teeth, and an increased risk of oral cancer.

Users of dipping tobacco are believed to face less risk of some cancers than smokers but are still at greater risk than people who do not use any tobacco products. They also have an equal risk of other health problems directly linked to nicotine such as increased rate of atherosclerosis.

Diagnosis includes determining the clinical signs and the medical history, with inquiry into possible routes of exposure. Clinical toxicologists, medical specialists in the area of poisoning, may be involved in diagnosis and treatment.

The main tool in diagnosing and assessing the severity of lead poisoning is laboratory analysis of the blood lead level (BLL).

Blood film examination may reveal basophilic stippling of red blood cells (dots in red blood cells visible through a microscope), as well as the changes normally associated with iron-deficiency anemia (microcytosis and hypochromasia). However, basophilic stippling is also seen in unrelated conditions, such as megaloblastic anemia caused by vitamin B12 (colbalamin) and folate deficiencies.

Exposure to lead also can be evaluated by measuring erythrocyte protoporphyrin (EP) in blood samples. EP is a part of red blood cells known to increase when the amount of lead in the blood is high, with a delay of a few weeks. Thus EP levels in conjunction with blood lead levels can suggest the time period of exposure; if blood lead levels are high but EP is still normal, this finding suggests exposure was recent. However, the EP level alone is not sensitive enough to identify elevated blood lead levels below about 35 μg/dL. Due to this higher threshold for detection and the fact that EP levels also increase in iron deficiency, use of this method for detecting lead exposure has decreased.

Blood lead levels are an indicator mainly of recent or current lead exposure, not of total body burden. Lead in bones can be measured noninvasively by X-ray fluorescence; this may be the best measure of cumulative exposure and total body burden. However this method is not widely available and is mainly used for research rather than routine diagnosis. Another radiographic sign of elevated lead levels is the presence of radiodense lines called lead lines at the metaphysis in the long bones of growing children, especially around the knees. These lead lines, caused by increased calcification due to disrupted metabolism in the growing bones, become wider as the duration of lead exposure increases. X-rays may also reveal lead-containing foreign materials such as paint chips in the gastrointestinal tract.

Fecal lead content that is measured over the course of a few days may also be an accurate way to estimate the overall amount of childhood lead intake. This form of measurement may serve as a useful way to see the extent of oral lead exposure from all the diet and environmental sources of lead.

Lead poisoning shares symptoms with other conditions and may be easily missed. Conditions that present similarly and must be ruled out in diagnosing lead poisoning include carpal tunnel syndrome, Guillain–Barré syndrome, renal colic, appendicitis, encephalitis in adults, and viral gastroenteritis in children. Other differential diagnoses in children include constipation, abdominal colic, iron deficiency, subdural hematoma, neoplasms of the central nervous system, emotional and behavior disorders, and intellectual disability.

Coal ash, also known as coal combustion residuals (CCRs), is the particulate residue that remains from burning coal. Depending on the chemical composition of the coal burned, this residue may contain toxic substances and pose a health risk to workers in coal-fired power plants.

In the United States, the only federal regulation regarding the disposal of coal ash is called “Disposal of Coal Combustion Residuals from Electric Utilities”, which was signed into law on December 19th, 2014. In addition, when coal ash is disposed into surface impoundments and landfills, coal ash is regulated as non-hazardous solid waste under the Resource Conservation and Recovery Act (RCRA). Thus, the requirements of the coal ash disposal law is regulated under subtitle D of the RCRA.

In order for this federal regulation to be effective, there are some major requirements that surface impoundments and landfill facilities must follow. This rule requires facilities to prevent and control coal ash dust from accumulating into the air. As a result, facilities must provide annual plans for coal ash dust control. Furthermore, there are location restrictions where new landfills and surface impoundments can be built. In addition, if regulations of coal ash dust control are not maintained, closure of the facility will occur under the federal law. The law also requires all coal ash waste facilities to create annual groundwater monitoring reports. Lastly, all coal ash waste surface impoundments and landfills must keep a written record of the federal regulations at the facility for five years. Ultimately, this recent federal regulation is trying to eliminate occupational health concerns and environmental health issues regarding coal ash toxicity.

Experiments for human toxicology require a long term following and a large amount of investment in order to classify a chemical as co-carcinogens, carcinogens or anti-carcinogenic. In recent years, people substitutes health supplement for healthy meal. Some myths even state beta carotene as elixir in developing country(The Third World).

With rising health consciousness, people rely on food supplements like vitamins A, B, C, D, E etc. these vitamins act as anti-oxidants chemical in the human body. Antioxidants is a good chemical in the appropriate consumption but a large overdose can cause cellular oxidation and cause cytopathic. Also, the industries can not strictly control the concentration and dose for supplement that extracted from natural food resources. A long-term consumption of those supplement can cause physical burden and also a significant hard work for organ to metabolize. Many health organization and government have published a maximum daily consumption for supplement called Tolerable Upper Intake Levels (UL), for example World Health Organization suggest the Tolerable Upper Intake Levels of Vitamin C is 2000 mg/d for adult men from age 31 to 50. Tolerable Upper Intake Levels is different for different gender and age. These suggested intake level can be followed in order to maintain the public health and safety.

Both animal and human experiment research shows that supplement cannot be the substitution to replace the daily food diet. Having a diverse diet and healthy habits is the better way to stay healthy instead of taking a lots of supplement that might be a co-carcinogen.

While sick building syndrome (SBS) encompasses a multitude of non-specific symptoms, building-related illness (BRI) comprises specific, diagnosable symptoms caused by certain agents (chemicals, bacteria, fungi, etc.). These can typically be identified, measured, and quantified. There are usually 4 causal agents in BRI; 1.) Immunologic, 2.) Infectious, 3.) toxic, and 4.) irritant. For instance, Legionnaire's disease, usually caused by "Legionella pneumophila", involves a specific organism which could be ascertained through clinical findings as the source of contamination within a building. SBS does not have any known cure; alleviation consists of removing the affected person from the building associated with non-specific symptoms. BRI, on the other hand, utilizes treatment appropriate for the contaminant identified within the building (e.g., antibiotics for Legionnaire's disease). In most cases, simply improving the indoor air quality (IAQ) of a particular building will attenuate, or even eliminate, the acute symptoms of SBS, while removal of the source contaminant would prove more effective for a specific illness, as in the case of BRI. Building-Related Illness is vital to the overall understanding of Sick Building Syndrome because BRI illustrates a causal path to infection, theoretically. Office BRI may more likely than not be explained by three events: “Wide range in the threshold of response in any population (susceptibility), a spectrum of response to any given agent, or variability in exposure within large office buildings." Isolating any one of the three aspects of office BRI can be a great challenge, which is why those who find themselves with BRI should take three steps, history, examinations, and interventions. History describes the action of continually monitoring and recording the health of workers experiencing BRI, as well as obtaining records of previous building alterations or related activity. Examinations go hand in hand with monitoring employee health. This step is done by physically examining the entire workspace and evaluating possible threats to health status among employees. Interventions follow accordingly based off the results of the Examination and History report.

Organophosphate pesticides are one of the top causes of poisoning worldwide, with an annual incidence of poisonings among agricultural workers varying from 3-10% per country.

Mold health issues are potentially harmful effects of molds.

Molds (US usage; British English "moulds") are ubiquitous in the biosphere, and mold spores are a common component of household and workplace dust. The United States Centers for Disease Control and Prevention reported in its June 2006 report, 'Mold Prevention Strategies and Possible Health Effects in the Aftermath of Hurricanes and Major Floods,' that "excessive exposure to mold-contaminated materials can cause adverse health effects in susceptible persons regardless of the type of mold or the extent of contamination." When mold spores are present in abnormally high quantities, they can present especially hazardous health risks to humans after prolonged exposure, including allergic reactions or poisoning by mycotoxins, or causing fungal infection (mycosis).

Aerotoxic syndrome is a phrase coined by Chris Winder and Jean-Christophe Balouet in 2000, to describe their claims of short- and long-term ill-health effects caused by breathing airliner cabin air which was alleged to have been contaminated to toxic levels (exceeding known, parts per million, safe levels) with atomized engine oils or other chemicals. Repeated investigations of such claims have failed to document cabin air has ever contained contaminants which exceeded known safe levels. An assessment by the UK's House of Lords Science and Technology Committee found that claims of health effects were unsubstantiated.

An update in 2008 found no significant new evidence. this syndrome is not recognized in medicine.

Symptoms of mold exposure can include:

- Nasal and sinus congestion, runny nose

- Respiratory problems, such as wheezing and difficulty breathing, chest tightness

- Cough

- Throat irritation

- Sneezing / Sneezing fits

Some research has suggested that high levels of fluoride exposure may adversely affect neurodevelopment in children, but the evidence is of insufficient quality to allow any firm conclusions to be drawn.

Some studies have shown a small difference between genders, with women having slightly higher reports of SBS symptoms compared to men. However, many other studies have shown an even higher difference in the report of sick building syndrome symptoms in women compared to men. It is not entirely clear, however, if this is due to biological, social, or occupational factors.

A 2001 study published in the Journal Indoor Air 2001 gathered 1464 office-working participants to increase the scientific understanding of gender differences under the Sick Building Syndrome phenomenon. Using questionnaires, ergonomic investigations, building evaluations, as well as physical, biological, and chemical variables, the investigators obtained results that compare with past studies of SBS and gender. The study team found that across most test variables, prevalence rates were different in most areas, but there was also a deep stratification of working conditions between genders as well. For example, men’s workplace tend to be significantly larger and have all around better job characteristics. Secondly, there was a noticeable difference in reporting rates, finding that women have higher rates of reporting roughly 20% higher than men. This information was similar to that found in previous studies, indicating a potential difference in willingness to report.

There might be a gender difference in reporting rates of sick building syndrome because women tend to report more symptoms than men do. Along with this, some studies have found that women have a more responsive immune system and are more prone to mucosal dryness and facial erythema. Also, women are alleged by some to be more exposed to indoor environmental factors because they have a greater tendency to have clerical jobs, wherein they are exposed to unique office equipment and materials (example: blueprint machines), whereas men often have jobs based outside of offices.

In 1986, the United States Congress commissioned a report by the National Research Council (NRC) into cabin air quality. The report recommended a ban on smoking on aircraft in order to improve air quality. In 1988, the FAA banned smoking on domestic flights of less than two hours, and in 2000 extended the ban to all domestic and international flights.

Research commissioned by the UK government's Department for Transport (DfT) and published in 2000 found no link to long term health. The UK Parliament's Select Committee on Science and Technology concluded in its response to the many complaints received "from a number of witnesses, particularly the Organophosphate Information Network, BALPA, and the International Association of Flight Attendants, expressing concerns about the risk of tricresyl phosphate (TCP or TOCP) poisoning for cabin occupants, particularly for crew who might be subjected to repeated exposure in some aircraft types, as a result of oil leaking into the cabin air supply."

In 2009 the UK House of Commons Library service to Members of Parliament summarized the research into a "relationship between the [engine oil chemical] leaks and these health symptoms" as inconclusive, citing "problems with identifying the exact chemical that might be entering the air supply and therefore identifying what impact it may have on health" and "reports of problems with fumes and/or health symptoms not being reported correctly".

According to a 2008 report by Michael Bagshaw, Aviation Medicine Director at King's College London, there have been no peer-reviewed recorded cases of neurological harm in humans following TCP exposure. He pointed to an unpublished report from the Medical Toxicology Unit at Guy's Hospital in 2001 which looked at all exposures dating back to 1943 that showed that all documented exposures were to high concentrations greatly in excess of the amount present in jet oil.

In his 2013 paper, "Cabin Air Quality: A review of current aviation medical understanding," Bagshaw noted further: "A German study in 2013 of 332 crew members who had reported fume/odour during their last flight, failed to detect metabolites of TCP in urine samples. The authors concluded that health complaints could not be linked to TCP exposure in cabin air...A syndrome is a symptom complex, consistent and common to a given condition. Sufferers of the ‘aerotoxic syndrome’ describe a wide range of inconsistent symptoms and signs with much individual variability."

The evidence was independently reviewed by the Aerospace Medical Association, the US National Academy of Sciences and the Australian Civil Aviation Safety Authority (CASA) Expert Panel. All concluded there is insufficient consistency to establish a medical syndrome, and the ‘aerotoxic syndrome’ is not recognised in aviation medicine."

The 'nocebo effect' was among the conclusions published in a 2013 COT (Committee on Toxicity) position paper: "The acute illness which has occurred in relation to perceived episodes of contamination might reflect a toxic effect of one or more chemicals, but it could also have occurred through nocebo effects. There is strong scientific evidence that nocebo effects can lead to (sometimes severely disabling) illness from environmental exposures that are perceived as hazardous."

A co-carcinogen is a chemical that promotes the effects of a carcinogen in the production of cancer. Usually, the term is used to refer to chemicals that are not carcinogenic on their own, such that an equivalent amount of the chemical is insufficient to initiate carcinogenesis. A chemical can be co-carcinogenic with other chemicals or with nonchemical carcinogens, such as UV radiation.

For example, sodium arsenite can be administered to mice at a low enough concentration that it does not cause tumors on its own, but it increases the rate of formation and size of tumors formed after UV exposure.

A chemical may act as a co-carcinogen even if it does not cause direct DNA damage such as mutation, as long as it can affect a cancer-related pathway. An example of this category includes chemicals within the phorbol ester family, which mimic a native signalling molecule. This ester is not mutagenic, but can increase the rate of cancer by promoting cell growth, a traditional hallmark of cancer.

A chemical may both have anti-carcinogenic properties and yet still be a co-carcinogen in combination with some carcinogens. Additionally, the carcinogenic modifying ability of a chemical can often be dose dependent, where low doses of the compound produce beneficial (or at least non-harmful) results (as in hormesis) while higher doses can lead to a toxic effect.

Evidence points to beta carotene being one example of such a compound, which has led researchers to caution against the emphasis on isolated dietary supplements and instead recommend a focus on promoting a diverse diet rich in fruits and vegetables.

Whilst fluoridated water is associated with decreased levels of fractures in a population, toxic levels of fluoride have been associated with a weakening of bones and an increase in hip and wrist fractures. The U.S. National Research Council concludes that fractures with fluoride levels 1–4 mg/L, suggesting a dose-response relationship, but states that there is "suggestive but inadequate for drawing firm conclusions about the risk or safety of exposures at [2 mg/L]".

Consumption of fluoride at levels beyond those used in fluoridated water for a long period of time causes skeletal fluorosis. In some areas, particularly the Asian subcontinent, skeletal fluorosis is endemic. It is known to cause irritable-bowel symptoms and joint pain. Early stages are not clinically obvious, and may be misdiagnosed as (seronegative) rheumatoid arthritis or ankylosing spondylitis.

Many occupational cancers are preventable. Personal protective gear, workplace controls, and worker education can prevent exposure to carcinogens in the workplace. Tobacco smoking has also been shown to increase the risk of work-related cancers; decreasing or abstaining from smoking can decrease cancer risk.

Agencies like the US Food and Drug Administration, Environmental Protection Agency, and Occupational Safety and Health Administration have developed safety standards and limits for chemical and radiation exposure.