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2 Diketene Acute Exposure Guideline Levels
Pages 41-61

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From page 41...
... Both the document and the AEGL values were then reviewed by the National Research Council (NRC) Committee on Acute Exposure Guideline Levels.
From page 42...
... Airborne concentrations below the AEGL-1 represent exposure concentrations that could produce mild and progressively increasing but transient and nondisabling odor, taste, and sensory irritation or certain asymptomatic, nonsensory effects. With increasing airborne concentrations above each AEGL, there is a progressive increase in the likelihood of occurrence and the severity of effects described for each corresponding AEGL.
From page 43...
... Diketene is irritating and much of its toxicity is likely caused by a direct chemical effect on the tissue; that type of portal-of-entry effect is not expected to vary greatly among individuals. The intraspecies uncertainty factor of 3 is further supported by the similarity in mortality incidence and clinical signs between male and female rats exposed to diketene (Katz 1987)
From page 44...
... Nonlethal Toxicity Occupational exposure to diketene at a concentration of 2 mg/m3 (0.58 ppm) for 1 min caused mild irritation of the conjunctiva and mucosa of the nose and throat (Danishevskii 1948,1951; Feldman 1967)
From page 45...
... No additional details on the experimental protocol were provided. One mouse died TABLE 2-3 Mortality and Clinical Signs in Rats Exposed to Diketene Exposure Concentration 0 250 500 750 0 250 500 750 Parameter No.
From page 46...
... No deaths occurred in rats and rabbits after exposure to diketene at 194 ppm for 10 min. Ocular and respiratorytract irritation were observed in rats exposed at lethal and nonlethal concentrations
From page 47...
... Ketene exposure caused severe damage to the respiratory tract (pulmonary edema) , but the pathologic effects were described only for cats.
From page 48...
... (1947) , guinea pigs died after exposure to diketene at 194 ppm for 10 min, but mice, rats, and rabbits survived a 10-min exposure at 194 ppm.
From page 49...
... DATA ANALYSIS FOR AEGL-2 6.1. Human Data Relevant to AEGL-2 No human data relevant to deriving AEGL-2 values for diketene were found.
From page 50...
... 7.2. Animal Data Relevant to AEGL-3 In an acute inhalation study using rats exposed to diketene vapor (250, 500, and 750 ppm)
From page 51...
... A factor of 3 is further supported by the fact that mortality incidences and clinical signs were similar between male and female rats exposed to diketene (Katz 1987)
From page 52...
... The ERPG-2 for diketene is based on clinical signs from a 1-h rat lethality study. The ERPG-3 is the maximum airborne concentration below which it is believed nearly all individuals could be exposed for up to 1 h without experiencing or developing lifethreatening health effects.
From page 53...
... 2001. Standing Operating Procedures for Developing Acute Exposure Guideline Levels for Hazardous Chemicals.
From page 54...
... That procedure is in accordance with the standing operating procedures for deriving AEGL values for chemicals with steep concentration-response curves (NRC 2001)
From page 55...
... Diketene 55 Modifying factor: 2 for limited database Calculations: 10-min AEGL-3: C3 = (1,647 ppm-min ÷ 10 min)
From page 56...
... That type of portal-of-entry effect is not expected to vary greatly among individuals. A factor of 3 is further supported by the fact that mortality incidences and clinical signs were similar between male and female rats exposed to diketene (Katz 1987)
From page 57...
... Additional studies in rats exposed for other durations and studies in at least one other species are needed to better characterize the acute inhalation toxicity of diketene.
From page 58...
... 58 Acute Exposure Guideline Levels APPENDIX C CATEGORY PLOT FOR DIKETENE FIGURE C-1 Category plot of toxicity data and AEGL values for diketene. TABLE C-1 Data Used in Category Plot for Diketene Source Species ppm Minutes Category Comments AEGL-2 1.8 10 AEGL AEGL-2 1.3 30 AEGL AEGL-2 1.0 60 AEGL AEGL-2 0.25 240 AEGL AEGL-2 0.13 480 AEGL AEGL-3 5.5 10 AEGL AEGL-3 3.8 30 AEGL AEGL-3 3.0 60 AEGL AEGL-3 0.75 240 AEGL AEGL-3 0.38 480 AEGL Danishevskii 1948, 1951; Human 0.58 1 1 Mild irritation of the Feldman 1967 conjunctiva and mucosa of nose and throat (Continued)
From page 59...
... 1947 Guinea pig 194 10 3 3/3 died For category: 0 = no effect, 1 = discomfort, 2 = disabling, SL = some lethality, 3 = lethality.
From page 60...
... Input Data File: C:\BMDS\DATA\DIKETENE.(d) Gnuplot Plotting File: C:\BMDS\DATA\DIKETENE.plt Mon Apr 09 09:49:14 2007 BMDS MODEL RUN The form of the probability function is: P[response]
From page 61...
... = 2 P-value = 0.8142 Benchmark Dose Computation Specified effect = 0.05 Risk type = Extra risk Confidence level = 0.95 BMD = 321.212 BMDL = 180.893


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