Nitrobenzene health effects

With regard to human health effects of 1,3-DNB, the few available studies involved acute-duration occupational exposure to 1,3-DNB by the inhalation and dermal routes, a case of accidental ingestion of a nitrobenzene dye, and a case of an experimenter who self-applied 1,3-DNB dermally for research purposes. No information was located on intermediate-or chronic-duration exposures in humans by any route. No information is available regarding immunologic, developmental, reproductive, genotoxic, or cancer effects in humans by any route of exposure. 

Human Health Effects from Breathing Nitrobenzene 1 -2 Animal Health Effects from Breathing Nitrobenzene... 

This Statement was prepared to give you information about nitrobenzene and to emphasize the human health effects that may result from exposure to it. The Environmental Protection Agency (EPA) has identified 1,177 sites on its National Priorities List (NPL). Nitrobenzene has been found at 7 of these sites. However, we do not know how many of the 1,177 NPL sites have been evaluated for nitrobenzene. As EPA evaluates more sites, the number of sites at which nitrobenzene is found may change. The information is important for you because nitrobenzene may cause harmful health effects and because these sites are potential or actual sources of human exposure to nitrobenzene. 

If you are exposed to a hazardous substance such as nitrobenzene, several factors will determine whether harmful health effects will occur and what the type and severity of those health effects will be. These factors include the dose (how much), the duration (how long), the route or pathway by which you are exposed (breathing, eating, drinking, or skin contact), the other chemicals to which you are exposed, and your individual characteristics such as age, sex, nutritional status, family traits, life style, and state of health. 

Further information on the health effects of nitrobenzene in humans and animals can be found in Chapter 2. More information on nitrobenzene breakdown products can be found in Chapter 2. There are populations that are unusually susceptible to nitrobenzene, and this is further discussed in Chapter 2. 

Tables 1-1 through 1-4 show the relationship between exposure to nitrobenzene at certain levels and known health effects. The exposure of laboratory animals to nitrobenzene through skin contact has resulted in harmful effects similar to those seen in laboratory animals by other routes of exposure. In general, the longer the period of contact with the skin, the more severe the effects.

The health effects resulting from short-term exposure of humans to air containing specific levels of nitrobenzene are not known. 

TABLE 1-3. Human Health Effects from Eating or Drinking Nitrobenzene... 

More information on the health effects associated with exposure to nitrobenzene is presented in Chapter 2. 

In cases of long-term exposure to nitrobenzene, the presence of its breakdown products, p-nitrophenol and p-aminophenol, in the urine is an indication of nitrobenzene exposure. These tests require special equipment and cannot be routinely done in a doctor s office. The results of these tests cannot be used to determine the level of nitrobenzene exposure or if harmful health effects can be expected to occur. 

The federal government has developed regulations and guidelines in order to protect individuals from the possible health effects of nitrobenzene in drinking water. The Environmental Protection Agency (EPA) has concluded that the amount of nitrobenzene in drinking water should not exceed... 

Health effects in humans following inhalation exposure to nitrobenzene have been described. However, as described in this section, these studies are limited in detail and technical content. There are several reliable animal studies using this route of exposure. 

Table 2-1 and Figure 2-1 describe the health effects observed in laboratory animals associated with inhalation of nitrobenzene at varying exposure levels and durations the results are discussed below. 

No studies were located regarding the following health effects in humans or animals after dermal exposure to nitrobenzene. 

Studies in animals, combined with observations in humans, indicate that the principal adverse health effects associated with short-term inhalation or oral exposure to nitrobenzene are methemoglobinemia, neurological effects, and liver injury. Data related to dermal exposure and to long-term exposure by any route are not considered sufficient to clearly assess the potential effects. 

Section 104(i)(5) of CERCLA, directs the Administrator of ATSDR (in consultation with the Administrator of EPA and agencies and programs of the Public Health Service) to assess whether adequate information on the health effects of nitrobenzene is available. Where adequate information is not available, ATSDR, in conjunction with the National Toxicology Program (NTP), is required to assure the initiation of a program of research designed to determine the health effects (and techniques for developing methods to determine such health effects) of nitrobenzene. 

FIGURE 2-3. Existing Information on Health Effects of Nitrobenzene... 

Epidemiological and Human Dosimetry Studies. No epidemiological studies were located regarding human health effects from nitrobenzene exposure. Studies of occupationally exposed populations would probably provide useful information. Areas of major interest would include methemoglobin levels, effects on reproductive function, immunological status, and neurobehavioral function. 

Because of its potential to cause adverse health effects in exposed people, a number of regulations and guidelines have been established for nitrobenzene by various international, national and state agencies. These values are summarized in Table 7-1. 

EPA. 1987c. Health effects assessment for nitrobenzene. Cincinnati, OH U.S. Environmental Protection Agency, Office of Research and Development. EPA/600/8-88/049. NTIS No. PB88-178975. 

Health and Safety Factors. The toxic effects of the mononitrotoluenes are similar to but less pronounced than those described for nitrobenzene. The maximum allowable concentration for the mononitrotoluenes is 2 ppm (11 mg/m ) (6). Mononitrotoluenes are low grade methemoglobin formers (4) and may be absorbed through the skin and respiratory tract. The toxicity of alkyl nitrobenzenes decreases with an increasing... 

Genotoxic Effects. The genotoxicity of nitrobenzene has been investigated in both in vitro and in vivo studies. The results of in vitro studies are presented in Table 2- 3. In vivo studies are described in Sections 2.2.1.7 and 2.22.1. The results of these studies are generally negative and do not suggest potential human health concerns. 

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