Acute Effects:
* Acute exposure to styrene in humans results in respiratory effects, such as mucous membrane irritation, eye irritation, and gastrointestinal effects.

Chronic Effects (Noncancer):
* Chronic exposure to styrene in humans results in effects on the CNS (Central Nervous System), with symptoms such as headache, fatigue, weakness, depression, CNS dysfunction (reaction time, memory, visuomotor speed and accuracy, intellectual function), and hearing loss, peripheral neuropathy (a condition of the nervous system that usually begins in the hands and/or feet with symptoms of numbness, tingling, burning and/or weakness), minor effects on some kidney enzyme functions and on the blood.
* Animal studies have reported effects on the CNS, liver, kidney, and eye and nasal irritation from inhalation exposure to styrene.
* Liver, blood, kidney, and stomach effects have been observed in animals following chronic oral exposure.

Reproductive/Developmental Effects:
* Increased frequency of spontaneous abortions and a decreased frequency of births were reported in a study on the reproductive effects of styrene in humans.
* Lung tumors have been observed in the offspring of orally exposed mice.

Cancer Risk:
* Several epidemiologic studies suggest that there may be an association between styrene exposure and an increased risk of leukemia and lymphoma.
* IARC has classified styrene as a Group 2B, possibly carcinogenic to humans.
* Styrene oxide, a product of styrene metabolism in the body, is an established mutagen and carcinogen and is believed to be the reason for the toxicity of styrene. Styrene oxide has been detected in workers exposed to styrene. IARC has classified this metabolite as a Group 2A, probable human carcinogen.

Styrene: EPA Regulated Hazardous Waste, listed as toxic chemical
"EPA has determined that emissions of these chemicals present a threat to human health"
"It is readily absorbed through all routes of exposure and tends to store in fatty tissues. Acute exposure causes eye and mucous membrane irritation, dizziness, and even death due to respiratory system paralysis." source: EPA

Potential for Accumulation:
Styrene is readily absorbed following inhalation exposure and ingestion, and is widely distributed throughout the body. A small amount is absorbed through the skin. The highest concentration of styrene is found in fat tissue. Styrene is rapidly metabolized to styrene oxide...Absorbed styrene is cleared from the body within 4 days. source: CCOHS

Children especially are more vulnerable to exposures than adults in communities faced with contamination of their air, water, soil, or food for the following factors:
1) Children weigh less than adults, resulting in higher doses of chemical exposure relative to body weight
2) The developing bodily systems of children can suffer permanent damage if toxic exposures occur during critical growth stages
3) Children have a breathing zone lower to the ground
4) Children consume three times as much air per pound of body
weight as an adult, drink three times as much water and eat three times as much food and thus are more susceptible to the effects of toxic chemicals
sources: Agency for Toxic Substances and Disease Registry (ATSDR) , CDC-INFO , VPIRG

The interaction between air pollution and exercise is so strong that health scientists typically use exercising volunteers in their research."

Recommendations include:
Do make sure teachers, coaches and recreation officials know about air pollution and act accordingly.
Most important, do be aware of the quality of the air you breathe!
Don't take air pollution lightly, it can hurt all of us!

The test for styrene and its breakdown products require special equipment and are not usually available at your doctor's office, but may be ordered by the doctor. Your doctor can take samples and send them to a testing laboratory. source: CDC-INFO

If you are concerned about being exposed to harmful levels of styrene, CDC-INFO advises you contact
your state health department and your regional EPA office: click here for contacts

The major way you can be exposed to styrene is by breathing air containing it. Styrene is found in city air and indoor air. Styrene is released into the air from industries that make and use styrene. It is also released from automobile exhaust and cigarette smoke. Styrene can enter your body through your lungs if you breathe contaminated air or through your stomach and intestines if you eat or drink contaminated food or water. Styrene can also pass through the skin into your body. source: CDC-INFO

When considering how well the experimental data can be applied to the general population, an uncertainty factor for human variability is used in developing the minimum risk levels (MRL). This uncertainty factor addresses the application of the MRL to sensitive populations, including children and the elderly, which may not have been involved in the study population on which the MRL is based. Therefore the MRLs are considered protective of these sensitive populations. source CDC-INFO, ATSDR

The MRL for styrene = 260 micrograms per cubic meter, which translates to ~60 ppb (at 25 °C/77 °F 1 ppm = 4.26 mg/m3, MRL translates to 61 ppb then) source ATSDR, EPA/TTN

"Workplace standards are typically not intended to be protective for the general population AND many are not protective for workers." - Greater Boston Physicians for Social Responsibility (GBPSR)

Other names for styrene (Wikipedia)
Vinyl benzene,
cinnamene
styrol
ethenylbenzene
phenethylene
phenylethene
diarex HF 77
styrolene
styropol

Related information:

“There are environmental standards set for many chemicals. These standards assume exposure 24 hours per day, 7 days per week, for varying numbers of years. Most of these environmental standards are set only for one environmental medium (ie. air, water, soil), and don’t take other pathways into account. Most also are set for adults, not children. The Hazardous Ambient Air Standard for styrene is 512 micrograms (µg)/m3 [~120ppb]. There are concerns about whether that standard is adequate. If there are concerns about a specific facility, we would suggest that you contact your local air pollution control district.”
-NRDCinfo senior scientists, Gina Solomon

The chronic inhalation REL from Cal/EPA OEHHA for styrene is 200 ppb
source: OEHHA

Texas Short-Term Screening Level = 91.8 ppb
According to the Texas Natural Resource Conservation Commission, no health effects are thought to occur below this level. "Short-term" levels refer to the average exposure level during one hour.
Texas Long-Term Screening Level = 9.18
According to the Texas Natural Resource Conservation Commission, no health effects are thought to occur below this level. "Long-term" levels refer to the average exposure level during a year (24 hours for benzene and ethylne dichloride)
ATSDR Chronic Minimal Risk Level = 59.9 ppb
According to hte America Toxic Substances and Disease Regsitry, there is no appreciable risk of non-cancer health effects from being exposed to concentrations up to this level over periods longer than one year.
source: Global Community Monitor (gcm)

It is important to note that, just because you can't smell it, it doesn't mean that it's not there - what does it mean if you are smelling the styrene odor? According to EPA / TTN, the odor threshold (the lowest concentration point at which you can smell it) for styrene is 0.32 parts per million (ppm), 320 ppb - that is over 5 times greater than the 60 ppb standard for kids (source EPA/TTN).

• Styrene enters the environment during the manufacture, use, and disposal of styrene-based products. It can be found in air, water, and soil.
• It is broken down in the air usually within 1 to 2 days.
• It evaporates from shallow soils and surface water.
• It doesn't stick easily to soils and sediments.
• It's broken down by bacteria in the soil and water.
• It's not expected to build up in animals.
• Styrene breaks down to half the amount within a few days in surface water; in groundwater, however, it takes between 6 weeks and 7.5 months.
  source ATSDR