A public health statement summarizes information about a hazardous substance. The information is taken from a toxicological profile developed by the Agency for Toxic Substances and Disease Registry's (ATSDR's) Division of Toxicology and Human Health Sciences (DTHHS). A toxicological profile is a thorough review of a hazardous substance.

This toxicological profile examines hydrogen sulfide and carbonyl sulfide. This section of the public health statement summarizes the DTHHS's findings on carbonyl sulfide describes the effects of exposure to it, and describes what you can do to limit that exposure.

The U.S. Environmental Protection Agency (U.S. EPA) identifies the most serious hazardous waste sites in the nation. U.S. EPA then includes these sites on the National Priorities List (NPL) and targets them for federal clean-up activities. U.S. EPA has found carbonyl sulfide in at least 4 of the 1,832 current or former NPL sites.

The total number of NPL sites evaluated for carbonyl sulfide is not known. However, the possibility remains that as more sites are evaluated, the number of sites at which carbonyl sulfide is found may increase. This information is important; these future sites may be sources of exposure, and exposure to carbonyl sulfide may be harmful.

When a contaminant is released from a large area such as an industrial plant or from a container such as a drum or bottle, it enters the environment. However, such a release doesn't always lead to exposure. You can only be exposed to a contaminant when you come in contact with it. That contact-and therefore that exposure-can occur when you breathe, eat, or drink the contaminant, or when it touches your skin.

Even if you're exposed to carbonyl sulfide, you might not be harmed. Whether you are harmed will depend on such factors as the dose (how much), the duration (how long), and how you are exposed. Harm might also depend on whether you've been exposed to any other chemicals, as well as your age, sex, diet, family traits, lifestyle, and state of health.

Carbonyl sulfide (COS) is a colorless gas that smells like rotten eggs; it does not have an odor when it is free from impurities. Carbonyl sulfide can also be called carbon oxide sulfide and carbon oxysulfide.

At concentrations of 135 micrograms per cubic meter (µg/m³) (0.055 ppm), people may be able to smell carbonyl sulfide in air.

Carbonyl sulfide is present in both natural and human-made sources. It can be found in volcanic gases, crude petroleum oil, sulfurous waters, marshes, and soils. It is in the emissions from diesel engines, natural gas and refinery emissions, and tobacco smoke.

Carbonyl sulfide does not have many commercial uses, as it is primarily used in small-scale chemical syntheses. It is an intermediate in the manufacture of certain herbicides. It may also be used in the agricultural industry as a grain fumigant.

Carbonyl sulfide can be released into the air, water, and soil at places where it is produced or used.

We know that carbonyl sulfide can enter your body from the air because health effects have been observed in studies with animals. We do not know how much or how fast it can enter your body.

We do not know how carbonyl sulfide is broken down in the body or how it leaves the body.

We have very little information on the health effects of carbonyl sulfide. Studies in animals show that nervous system effects can occur after short-or long-term exposure. The health effects of carbonyl sulfide appear to depend on several factors such as how much you are exposed to and the length of that exposure.

Animal studies show that exposure to high levels of carbonyl sulfide in the air can damage the areas of the brain that control movement and process sound information.

No human or animal studies have examined whether carbonyl sulfide exposure can cause cancer.

DHHS, the International Agency for Research on Cancer (IARC), and EPA have not classified carbonyl sulfide as to its carcinogenicity.

There is no information on possible health problems in children who have been exposed to carbonyl sulfide. Exposed children probably will experience effects similar to those experienced by exposed adults. Whether children are more sensitive to carbonyl sulfide exposure than adults is not known.

It is not known if exposure to carbonyl sulfide causes birth defects in humans. No studies looked for birth defects in animals.

Carbonyl sulfide is part of the natural environment; the general population will have some exposure to carbonyl sulfide. Families can be exposed to more carbonyl sulfide than the general population if they live near natural or industrial sources of carbonyl sulfide, such as wetlands, volcanos, or coal combustion. However, their exposure levels are unlikely to approach those that sicken people exposed at work.

Families can reduce their exposure to carbonyl sulfide by avoiding areas that are sources of carbonyl sulfide.

Regulations are enforceable by law. The U.S. EPA, the Occupational Safety and Health Administration (OSHA), and the Food and Drug Administration (FDA) are some federal agencies that have adopted toxic substances regulations.

The Agency for Toxic Substances and Disease Registry (ATSDR) and the National Institute for Occupational Safety and Health (NIOSH) have made recommendations about toxic substances. Unlike enforceable regulations, these recommendations are advisory only.

Regulations and recommendations can be expressed as "not-to-exceed" levels; that is, levels of a toxic substance in air, water, soil, or food that do not exceed a critical value usually based on levels that affect animals; levels are then adjusted to help protect humans. Sometimes these not-to-exceed levels differ among federal organizations. Different organizations use different exposure times (an 8-hour workday or a 24-hour day), different animal studies, or emphasize some factors over others, depending on their mission.

Recommendations and regulations are also updated periodically as more information becomes available. For the most current information, check with the federal agency or organization that issued the regulation or recommendation.

Some regulations and recommendations for carbonyl sulfide exposure in workers include: