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3
Selected Chlorosilanes1
Acute Exposure Guideline Levels
PREFACE
Under the authority of the Federal Advisory Committee Act (FACA) P.L.
92-463 of 1972, the National Advisory Committee for Acute Exposure Guide-
line Levels for Hazardous Substances (NAC/AEGL Committee) has been estab-
lished to identify, review, and interpret relevant toxicologic and other scientific
data and develop AEGLs for high-priority, acutely toxic chemicals.
AEGLs represent threshold exposure limits for the general public and are
applicable to emergency exposure periods ranging from 10 minutes (min) to 8
hours (h). Three levels—AEGL-1, AEGL-2, and AEGL-3—are developed for
each of five exposure periods (10 and 30 min and 1, 4, and 8 h) and are distin-
guished by varying degrees of severity of toxic effects. The three AEGLs are
defined as follows:
AEGL-1 is the airborne concentration (expressed as parts per million or
milligrams per cubic meter [ppm or mg/m3]) of a substance above which it is
predicted that the general population, including susceptible individuals, could
experience notable discomfort, irritation, or certain asymptomatic, nonsensory
effects. However, the effects are not disabling and are transient and reversible
upon cessation of exposure.
1
This document was prepared by the AEGL Development Team composed of Chery
Bast (Oak Ridge National Laboratory), Julie M. Klotzbach (Syracuse Research Corpora-
tion), and Chemical Manager Ernest V. Falke (National Advisory Committee [NAC] on
Acute Exposure Guideline Levels for Hazardous Substances). The NAC reviewed and
revised the document and AEGLs as deemed necessary. Both the document and the
AEGL values were then reviewed by the National Research Council (NRC) Committee
on Acute Exposure Guideline Levels. The NRC committee has concluded that the
AEGLs developed in this document are scientifically valid conclusions based on the data
reviewed by the NRC and are consistent with the NRC guidelines reports (NRC 1993,
2001).
106
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107
Selected Chlorosilanes
AEGL-2 is the airborne concentration (expressed as ppm or mg/m3) of a
substance above which it is predicted that the general population, including sus-
ceptible individuals, could experience irreversible or other serious, long-lasting
adverse health effects or an impaired ability to escape.
AEGL-3 is the airborne concentration (expressed as ppm or mg/m3) of a
substance above which it is predicted that the general population, including sus-
ceptible individuals, could experience life-threatening health effects or death.
Airborne concentrations below the AEGL-1 represent exposure concentra-
tions that could produce mild and progressively increasing but transient and
nondisabling odor, taste, and sensory irritation or certain asymptomatic, nonsen-
sory 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. Although the AEGL values represent
threshold levels for the general public, including susceptible subpopulations,
such as infants, children, the elderly, persons with asthma, and those with other
illnesses, it is recognized that individuals, subject to idiosyncratic responses,
could experience the effects described at concentrations below the correspond-
ing AEGL.
SUMMARY
Chlorosilanes contain one or more chlorine atoms covalently bonded to a
silicon atom; the maximum chlorine-to-silicon ratio is four. Chlorosilanes are
chemical intermediates used in the production of silicone and silicone-
containing materials, and are often produced in bulk and transported to manufac-
turing sites for use. Chlorosilanes are corrosive, and inhalation exposure might
cause nasal, throat, or lung irritation, coughing, wheezing, and shortness of
breath. Chlorosilanes react rapidly with water, steam, or moisture; hydrolysis
yields hydrogen chloride (HCl) gas along with silanols and other condensation
products.
The 26 chlorosilanes considered in this chapter are:
Allyl trichlorosilane Methyl dichlorosilane
Amyl trichlorosilane Methyl trichlorosilane
Butyl trichlorosilane Methylvinyl dichlorosilane
Chloromethyl trichlorosilane Nonyl trichlorosilane
Dichlorosilane Octadecyl trichlorosilane
Diethyl dichlorosilane Octyl trichlorosilane
Dimethyl chlorosilane Propyl trichlorosilane
Dimethyl dichlorosilane Tetrachlorosilane
Diphenyl dichlorosilane Trichloro(dichlorophenyl)silane
Dodecyl trichlorosilane Trichlorophenylsilane
Ethyl trichlorosilane Trichlorosilane
Hexyl trichlorosilane Trimethyl chlorosilane
Methyl chlorosilane Vinyl trichlorosilane
107
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108 Acute Exposure Guideline Levels
Although chemical-specific toxicity data are not available for many of
these chlorosilanes, acute inhalation data from rat studies are available for struc-
turally-similar chlorosilanes (propyl trichlorosilane, methyl trichlorosilane, vinyl
trichlorosilane, ethyl trichlorosilane, methylvinyl dichlorosilane, methyl dichlo-
rosilane, dimethyl dichlorosilane, dimethyl chlorosilane, trimethylchlorosilane,
and tetrachlorosilane). These data suggest that the acute toxicity of chlorosilanes
is largely explained by the HCl hydrolysis product; acute toxicity of these chlo-
rosilanes is qualitatively (based on clinical signs) and quantitatively (based on
molar equivalents of HCl) similar to that of HCl (Jean et al. 2006).
On the basis of these data, and in the absence of appropriate chemical-
specific data for the chlorosilanes considered in this document, the AEGLs for
HCl were used to derive AEGLs for the chlorosilanes. For each class of chloro-
silanes (mono-, di-, tri-, and tetra-chlorosilanes), the molar ratio (moles of HCl
released per mole of chlorosilane, assuming complete hydrolysis) was used to
adjust the AEGL values for HCl to the equivalent concentration of chlorosilane.
Detailed information on the derivation of AEGLs for HCl is available in NRC
(2004). The calculated values are listed in the Table 3-1.
1. INTRODUCTION
Chlorosilanes contain one or more chlorine atoms covalently bonded to a
silicon atom; the maximum chlorine-to-silicon ratio is four. Chlorosilanes are
chemical intermediates used in the production of silicone and silicone-
containing materials, and are often produced in bulk and transported to manufac-
turing sites for use.
Chlorosilanes react very rapidly with water, steam, or moisture, releasing
HCl gas (AIHA 1998, 1999, 2001a,b,c, 2006). The primary vapor detected in air
when chlorosilanes are released is HCl; much less of the parent chlorosilane is
detectable (Nakashima et al. 1996; Jean et al. 2006). In an experiment using 11
different chlorosilanes, Jean et al. (2006) reported that the percentage of parent
chlorosilane in the test atmosphere ranged from <10% to 58%; other constitu-
ents of the atmosphere (in addition to HCl) included silanols and other conden-
sation products. When x-ray microanalysis was performed on air filtered from a
dichlorosilane exposure chamber, small (<1 µM in diameter), unidentified parti-
cles containing silicon and chloride were detected (Nakashima et al. 1996).
Numerous reports of chlorosilane spills and releases have been received
by the U.S. Coast Guard National Response Center. For example, between Janu-
ary 1990 and July 2007, there were 23 reports of dichlorosilane releases ranging
from 6 to 2,596 pounds; 32 reports of trichlorosilane releases ranging from 2.6
to 343 pounds; and 14 reports of tetrachlorosilane releases ranging from 2 to 330
pounds (USCG 2007). Releases were from both fixed and mobile sources and
were the result of equipment failure and operator error.
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TABLE 3-1 Summary of AEGL Values for Selected Chlorosilanesa
Compound Classification 10 min 30 min 1h 4h 8h End Point (Reference)
MONOCHLOROSILANES
Dimethyl chlorosilane AEGL-1 1.8 ppm 1.8 ppm 1.8 ppm 1.8 ppm 1.8 ppm AEGLs for HCl
AEGL-2 100 ppm 43 ppm 22 ppm 11 ppm 11 ppm (NRC 2004)
Methyl chlorosilane
AEGL-3 620 ppm 210 ppm 100 ppm 26 ppm 26 ppm
Trimethylchlorosilane
DICHLOROSILANES
Dichlorosilane AEGL-1 0.90 ppm 0.90 ppm 0.90 ppm 0.90 ppm 0.90 ppm AEGLs for HCl
AEGL-2 50 ppm 22 ppm 11 ppm 5.5 ppm 5.5 ppm divided by a molar
Diethyl dichlorosilane
AEGL-3 310 ppm 110 ppm 50 ppm 13 ppm 13 ppm adjustment factor of 2
Dimethyl dichlorosilane
(NRC 2004)
Diphenyl dichlorosilane
Methyl dichlorosilane
Methylvinyl dichlorosilane
TRICHLOROSILANES
Allyl trichlorosilane AEGL-1 0.60 ppm 0.60 ppm 0.60 ppm 0.60 ppm 0.60 ppm AEGL values for HCl
AEGL-2 33 ppm 14 ppm 7.3 ppm 3.7 ppm 3.7 ppm divided by a molar
Amyl trichlorosilane
AEGL-3 210 ppm 70 ppm 33 ppm 8.7 ppm 8.7 ppm adjustment factor of 3
Butyl trichlorosilane
(NRC 2004)
Chloromethyl trichlorosilane
Dodecyl trichlorosilane
Ethyl trichlorosilane
Hexyl trichlorosilane
Methyl trichlorosilane
Nonyl trichlorosilane
Octadecyl trichlorosilane
Octyl trichlorosilane
Propyl trichlorosilane
109
(Continued)
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110
TABLE 3-1 Continued
Compound Classification 10 min 30 min 1h 4h 8h End Point (Reference)
TRICHLOROSILANES (continued)
Trichloro(dichlorophenyl)silane
Trichlorophenylsilane
Trichlorosilane
Vinyl trichlorosilane
TETRACHLOROSILANE
AEGL-1 0.45 ppm 0.45 ppm 0.45 ppm 0.45 ppm 0.45 ppm AEGL values for HCl
AEGL-2 25 ppm 11 ppm 5.5 ppm 2.8 ppm 2.8 ppm divided by a molar
AEGL-3 160 ppm 53 ppm 25 ppm 6.5 ppm 6.5 ppm adjustment factor of 4
(NRC 2004)
a
Values given in ppm. To convert ppm to mg/m3: (ppm × molecular weight) ÷ 24.5. See Appendix A for the appropriate molecular weight. For
mono-, di-, and tri-chlorosilanes not listed, use of HCl equivalents may be considered for AEGL-value derivation.
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111
Selected Chlorosilanes
The chlorosilanes have pungent irritating odors, are corrosive, and inhala-
tion exposure might cause nasal, throat, or lung irritation, coughing, wheezing,
and shortness of breath. Although chemical-specific toxicity data are not avail-
able for many of the chlorosilanes, acute inhalation data from rat studies are
available for structurally-similar chlorosilanes (propyl trichlorosilane, methyl
trichlorosilane, vinyl trichlorosilane, ethyl trichlorosilane, methylvinyl dichloro-
silane, methyl dichlorosilane, dimethyl dichlorosilane, dimethyl chlorosilane,
trimethylchlorosilane, and tetrachlorosilane). These data suggest that the acute
toxicity of chlorosilanes is from the HCl hydrolysis product; acute toxicity of the
chlorosilanes is qualitatively (based on clinical signs) and quantitatively (based
on molar equivalents of HCl) similar to that of HCl (Jean et al. 2006) (see Sec-
tion 4.3).
On the basis, and in the absence of adequate chemical-specific data for the
chlorosilanes considered in this document, the AEGL values for HCl (NRC
2004) were used to obtain AEGL values for the chlorosilanes. The molar ratio
(moles HCl released per mole of chlorosilane, assuming complete hydrolysis)
was used to adjust the AEGL values for HCl to the equivalent concentration of
chlorosilane. Available physicochemical data for the 26 chlorosilanes covered in
this chapter are presented in Appendix A.
2. HUMAN TOXICITY DATA
An accidental release of tetrachlorosilane at a chemical plant in a south
San Francisco industrial park provided some human exposure data (Kizer et al.
1984). A delivery truck taking a short-cut through a chemical plant hit the tank-
coupling unit of a tetrachlorosilane storage tank. The pipeline ruptured and the
tetrachlorosilane liquid spilled onto the moist ground; it hydrolyzed rapidly and
formed a large gray-white cloud that quickly spread. Workers were unable to
stop the leak because the valve was behind a wire enclosure, and approximately
1,200 gallons of tetrachlorosilane was released before the leak was stopped sev-
eral hours later. By that time, the cloud had risen 500 feet and had spread more
than a mile over the industrial park. Five- to ten-thousand employees from 600
businesses over 3 square miles were evacuated. Twenty-eight people reported to
local hospitals for treatment of eye or airway irritation. Seven of the patients
were employees at the chemical plant, and six of them were smokers. The re-
maining 21 patients were firemen, policemen, passersby, and employees of other
companies in the area. There were no deaths, and no one was hospitalized. Six
of the chemical plant employees were referred for further evaluation; these em-
ployees were all male, ranged in age from 25 to 56, and were all smokers. Their
exposures ranged from 10 to 20 min in duration. Symptoms generally resolved
within 24 h, and included lacrimation, rhinorrhea, burning of the mouth and
throat, headache, coughing, and wheezing. Pulmonary function tests were nor-
mal except that mild obstructive airway disease was noted in four patients.
However, it was unclear if the disease was from exposure to tetrachlorosilane or
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112 Acute Exposure Guideline Levels
related to smoking status. Two patients also complained of pedal dysesthesias
after the accident. No air concentrations of tetrachlorosilane or HCl were re-
ported.
Reactive airways dysfunction syndrome is an asthma-like condition that
develops after a single exposure to high concentrations of a chemical irritant,
and has been described after exposure to HCl. Symptoms occur within minutes
to hours after the initial exposure and can persist as nonspecific bronchial hyper-
responsiveness for months to years (Bernstein 1993). Promisloff et al. (1990)
reported reactive airways dysfunction syndrome in three male police officers
(36-45 years of age) who responded to a roadside chemical spill. The subjects
were exposed to unquantified amounts of sodium hydroxide, tetrachlorosilane,
and HCl as a byproduct of trichlorosilane hydrolysis. Because of the mixture of
irritants involved in the release, it is probable that all of the compounds contrib-
uted to the syndrome observed after this accident.
3. ANIMAL TOXICITY DATA
3.1. Acute Toxicity
One-hour LC50 (lethal concentration, 50% lethality) studies were con-
ducted for 10 chlorosilanes: tetrachlorosilane, propyl trichlorosilane, vinyl tri-
chlorosilane, methyl trichlorosilane, ethyl trichlorosilane, methylvinyl dichloro-
silane, dimethyl dichlorosilane, methyl dichlorosilane, trimethyl chlorosilane,
and dimethyl chlorosilane (Jean et al. 2006). In each study, groups of five male
and five female Fischer 344 rats were exposed to varying concentrations of a
chlorosilane for 1 h and observed for up to 14 days. The studies appeared to
conform to Good Laboratory Practices and were well-described. The authors
used nominal concentrations to calculate LC50 values because chlorosilanes react
rapidly with moisture to produce HCl and other hydrolysis products. Using ac-
tual chamber concentrations of chlorosilanes would only reflect toxicity of the
parent compound, not the toxicity of the parent compound and hydrolysis prod-
ucts. There was agreement between the electrolytic conductivity detector and the
nominal concentrations, indicating efficient vaporization of the test material.
Clinical signs were consistent with HCl exposure and included lacrima-
tion, salivation, dried material around the eyes or nose, green staining around the
nose and mouth, and perineal urine staining. Labored breathing, rales, hypoac-
tivity, closed or partially closed eyes, prostration, corneal opacity or opaqueness,
and swollen or necrotic paws also were observed. Hemorrhage, congestion, and
consolidation of the lungs; ectasia of the lungs; gaseous distension of the gastro-
intestinal tract; absence of body fat; obstruction of nostrils; dried or firm nares;
alopecia around the eyes; and discoloration of hair were observed at necropsy.
Mortality data and LC50 values from 1-h exposure studies with rats are summa-
rized in Table 3-2.
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113
Selected Chlorosilanes
TABLE 3-2 Mortality Data and LC50 Values from 1-Hour Exposure Studies
with Rats
Exposure Mortality LC50, ppm
Concentration (95% confidence
Compound (ppm) Male Female Total limits)
1,312 (1,006-1,529) a
Tetrachlorosilane 1,209 1/5 2/5 3/10
1,497 5/5 3/5 8/10
3,051 5/5 5/5 10/10
1,352 (1,254-1,455) a
Propyl trichlorosilane 1,123 0/5 0/5 0/10
1,317 2/5 2/5 4/10
1,414 3/5 4/5 7/10
1,611 (1,505-1,724) b
Vinyl trichlorosilane 1,186 0/5 0/5 0/10
1,605 4/5 2/5 6/10
1,681 2/5 1/5 3/10
1,989 5/5 5/5 10/10
1,365 (1,174-2,104) a
Methyl trichlorosilane 622 0/5 0/5 0/10
1,047 0/5 1/5 1/10
1,439 4/5 2/5 6/10
3,075 5/5 5/5 10/10
1,257 (1,175-1,320) a
Ethyl trichlorosilane 1,156 1/5 1/5 2/10
1,326 4/5 2/5 6/10
1,415 5/5 5/5 10/10
2,021 (1,806-2,257) a
Methylvinyl 1,597 1/5 0/5 1/10
dichlorosilane 2,005 3/5 2/5 5/10
2,119 3/5 3/5 6/10
2,242 4/5 3/5 7/10
2,092 (1,492-2,240) a
Dimethyl 1,309 0/5 0/5 0/10
dichlorosilane 2,077 4/5 1/5 5/10
2,353 5/5 3/5 8/10
2,762 5/5 5/5 10/10
1,785 (1,671-1,963) a
Methyl 1,431 0/5 0/5 0/10
dichlorosilane 1,678 1/5 2/5 3/10
1,889 4/5 3/5 7/10
4,257 (4,039-4,488) b
Trimethyl 3,171 0/5 0/5 0/10
chlorosilane 4,139 2/5 0/5 2/10
4,268 3/5 3/5 6/10
5,121 5/5 5/5 10/10
4,478 (4,281-6,327) a
Dimethyl 4,108 1/5 1/5 2/10
chlorosilane 4,179 1/5 1/5 2/10
4,409 3/5 3/5 6/10
4,589 3/5 2/5 5/10
a
Probit analysis.
b
Spearman-Karber analysis.
Source: Jean et al. 2006. Reprinted with permission; copyright 2006, Inhalation Toxi-
cology.
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114 Acute Exposure Guideline Levels
In another study, groups of 10 male ICR mice were exposed for 4 h to
nominal concentrations of dichlorosilane at 49-259 ppm, followed by a 14-day
observation period (Nakashima et al. 1996). Mortality was 0/10, 0/10, 1/10,
6/10, 4/10, 10/10, 10/10, 9/10, and 10/10 for groups exposed at 0, 49, 100,
131, 141, 199, 216, 218, and 259 ppm, respectively. An LC50 of 144 ppm was
calculated.
3.2. Developmental and Reproductive Toxicity
No data on developmental or reproductive toxicity were found.
3.3. Genotoxicity
The only genotoxicity data found were for tetrachlorosilane. Tetrachloro-
silane was not mutagenic in Salmonella typhimurium strains TA98, TA100, TA
1535, TA1537, or TA1538; Saccharomyces cerevisiae strain D-4; or Escheris-
chia coli strains W3110/polA+ and P3478/polA- either with or without metabolic
activation. It was also negative in a L5178Y mouse lymphoma assay (AIHA
1999).
3.4. Chronic Toxicity and Carcinogenicity
No data on chronic toxicity or carcinogenicity were found.
3.5. Summary
Although toxicity data are sparse for individual chlorosilanes, well-
conducted 1-h inhalation toxicity studies in rats are available for a series of chlo-
rosilanes (Jean et al. 2006). In general, LC50 values for monochlorosilanes were
approximately twice the LC50 values for dichlorosilanes and three times the LC50
values for trichlorosilanes. Tetrachlorosilane had an LC50 value similar to the
trichlorosilanes; however, there were experimental difficulties at the lowest con-
centration tested. Clinical signs were indicative of severe irritation or corrosion.
The evidence suggests that the acute toxicity of chlorosilanes is largely attribut-
able to the release of HCl; however, no information on the identity or potential
toxicity of other decomposition products was found. No data concerning devel-
opmental or reproductive toxicity, genotoxicity, or carcinogenicity for exposure
to the chlorosilanes were found in the literature.
4. SPECIAL CONSIDERATIONS
4.1. Metabolism and Disposition
No information was found concerning the metabolism and disposition of
chlorosilanes.
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115
Selected Chlorosilanes
4.2. Mechanism of Toxicity
Chlorosilanes react violently with water to produce HCl gas (AIHA 1998,
1999, 2001a,b,c, 2006). In an experiment using 11 different chlorosilanes, Jean
et al. (2006) reported that the percentage of parent chlorosilane in the test at-
mosphere range from <10 to 58%; other constituents of the atmosphere (in addi-
tion to HCl) included silanols and other condensation products. Nakashima et al.
(1996) reported that small particles containing silicon and chlorine were de-
tected in an inhalation exposure chamber into which dichlorosilane was intro-
duced; the identity and quantity of particles were not reported. IPCS (2002a)
reported that, when heated, trimethylchlorosilane decomposition could release
HCl and phosgene. No other information on potential decomposition products of
chlorosilanes was found. Available data suggest that the acute toxicity of chloro-
silanes is largely from the HCl hydrolysis product; acute toxicity of the chlorosi-
lanes is qualitatively (based on clinical signs) and quantitatively (based on molar
equivalents of HCl) similar to that of HCl.
4.3. Structure Activity Relationships
A 1-h LC50 study with HCl was performed in rats and used for comparison
with the chlorosilane 1-h LC50 values (Jean et al. 2006). According to the au-
thors, the study with HCl was unpublished, but was performed in the same labo-
ratory and was conducted using the same protocol as that used in the chlorosi-
lane study (1-h whole-body exposure with a 14-day recovery period). Five rats
per sex were exposed to HCl at 0, 2,456, 3,236, or 4,210 ppm for 1 h and ob-
served for up to 14 days. Chamber concentrations were determined by a Fourier
transform infrared spectrophotometer analyzer. Clinical signs included labored
breathing; gasping; emaciation; rough coat; lethargy; corneal opacity; crusting,
necrotic, discolored, and blocked nares or nasal opening; paws with missing,
necrotic, or swollen digits; and weight loss. Gross pathology of animals dying
during the study included irritation and necrosis of most extremities, severe res-
piratory-tract injuries, and corneal opacity. A 1-h LC50 of 3,627 ppm was calcu-
lated for HCl.
The LC50 data obtained for the chlorosilanes showed a strong association
with chlorine content for the mono-, di-, and tri-chlorosilanes. In general, LC50
values for monochlorosilanes were approximately twice the LC50 values for di-
chlorosilanes and three times the LC50 values for trichlorosilanes. Tetrachlorosi-
lane exhibited an LC50 value similar to the trichlorosilanes.
The predicted 1-h LC50 values for the chlorosilanes, based on HCl equiva-
lents, are presented in Table 3-3. The predicted values for the chlorosilanes are
comparable to the experimentally-derived 1-h LC50 values (log * log regression
analysis of chlorosilane LC50 values vs. the number of chlorine groups yielded
an r2 value of 0.97). The data suggest that the acute toxicity of the chlorosilanes
is similar to or slightly less than what would be expected based on HCl molar
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116 Acute Exposure Guideline Levels
equivalents. The within-class LC50 values were not significantly influenced by
the number or type of hydrocarbon R-group(s) present (methyl, ethyl, propyl, or
vinyl). Cases where the predicted value is less might be attributed to incomplete
hydrolysis in the test atmosphere; however, continued hydrolysis and generation
of HCl would be expected for any remaining chlorosilane when in contact with
moist tissues (mucous membranes, lung) (Jean et al. 2006). This information
taken in conjunction with the observed clinical signs suggests that the acute tox-
icity of the chlorosilanes is quantitatively and qualitatively similar to HCl and
that the HCl hydrolysis product is responsible for the acute toxicity of the chlo-
rosilanes.
TABLE 3-3 Measured and Predicted 1-Hour LC50 Values for Selected
Chlorosilanes
Measured Predicted Measured
Predicted
LC50 (ppm) (95% Ratio of Ratio of LC50
Compound confidence limits) LC50 (ppm) LC50 Values Values
Hydrogen chloride 3,627
Tetrachlorosilane 1,312 (1,006-1,529) 3,627 ÷ 4 = 907 4:1 2.8:1
Propyl trichlorosilane 1,352 (1,254-1,455) 3,627 ÷ 3 = 1,209 3:1 2.7:1
Vinyl trichlorosilane 1,611 (1,505-1,724) 3,627 ÷ 3 = 1,209 3:1 2.3:1
Methyl trichlorosilane 1,365 (1,174-2,104) 3,627 ÷ 3 = 1,209 3:1 2.7:1
Ethyl trichlorosilane 1,257 (1,175-1,320) 3,627 ÷ 3 = 1,209 3:1 2.9:1
Methylvinyl 2,021 (1,806-2,257) 3,627 ÷ 2 = 1,814 2:1 1.8:1
dichlorosilane
Dimethyl 2,092 (1,492-2,240) 3,627 ÷ 2 = 1,814 2:1 1.7:1
dichlorosilane
Methyl 1,785 (1,671-1,963) 3,627 ÷ 2 = 1,814 2:1 2:1
dichlorosilane
Trimethyl 4,257 (4,039-4,488) 3,627 ÷ 1 = 3,627 1:1 0.9:1
chlorosilane
Dimethyl 4,478 (4,281-6,327) 3,627 ÷ 1 = 3,627 1:1 0.8:1
chlorosilane
Source: Adapted from Jean et al. 2006.
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156 Acute Exposure Guideline Levels
AEGL-1 VALUES FOR TRICHLOROSILANES
10 min 30 min 1h 4h 8h
0.60 ppm 0.60 ppm 0.60 ppm 0.60 ppm 0.60 ppm
Key reference: NRC (National Research Council). 2004. Hydrogen chloride.
Pp. 77-122 in Acute Exposure Guideline Levels for Selected Airborne
Chemicals, Vol. 4. Washington, DC: National Academies Press.
End point/Concentration/Rationale: AEGL-1 values for trichlorosilanes were
derived by adjusting the AEGL-1 values for HCl by the molar ratio of HCl to
trichlorosilanes. This approach is considered reasonable because qualitative and
quantitative data on chlorosilanes suggest that the HCl hydrolysis product is
largely responsible for the acute toxicity of the chlorosilanes.
Molar Adjustment Factor: 3
Data adequacy: Mechanism-of-action data were considered adequate for the
derivation of AEGL-1 values for chlorosilanes based on analogy to HCl.
Confidence in the AEGL-1 values for chlorosilanes is low, reflecting the lack of
data on AEGL-1 end points after chlorosilane exposure and reliance on HCl data.
Additional research on AEGL-1 effects of chlorosilanes would reduce uncertainty.
AEGL-1 VALUES FOR TETRACHLOROSILANE
10 min 30 min 1h 4h 8h
0.45 ppm 0.45 ppm 0.45 ppm 0.45 ppm 0.45 ppm
Key reference: NRC (National Research Council). 2004. Hydrogen chloride. Pp.
77-122 in Acute Exposure Guideline Levels for Selected Airborne Chemicals,
Vol. 4. Washington, DC: National Academies Press.
End point/Concentration/Rationale: AEGL-1 values for tetrachlorosilane were
derived by adjusting the AEGL-1 values for HCl by the molar ratio of HCl to
tetrachlorosilane. This approach is considered reasonable because qualitative
and quantitative data on chlorosilanes suggest that the HCl hydrolysis product
is largely responsible for the acute toxicity of the chlorosilanes.
Molar adjustment factor: 4
Data adequacy: Mechanism-of-action data were considered adequate for
the derivation of AEGL-1 values for chlorosilanes based on analogy to HCl.
Confidence in the AEGL-1 values for chlorosilanes is low, reflecting the lack
of data on AEGL-1 end points after chlorosilane exposure and reliance on HCl
data. Additional research on AEGL-1 effects of chlorosilanes would reduce
uncertainty.
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157
Selected Chlorosilanes
AEGL-2 VALUES FOR MONOCHLOROSILANES
10 min 30 min 1h 4h 8h
100 ppm 43 ppm 22 ppm 11 ppm 11 ppm
Key reference: NRC (National Research Council). 2004. Hydrogen chloride.
Pp. 77-122 in Acute Exposure Guideline Levels for Selected Airborne
Chemicals, Vol. 4. Washington, DC: National Academies Press.
End point/Concentration/Rationale: AEGL-2 values for HCl were adopted as
AEGL-2 values for monochlorosilanes. This approach is considered reasonable
because qualitative and quantitative data on chlorosilanes suggest that the HCl
hydrolysis product is largely responsible for the acute toxicity of the chlorosilanes.
Data adequacy: Mechanism-of-action data were considered adequate for the
derivation of AEGL-2 values for chlorosilanes based on analogy to HCl.
Confidence in the AEGL-2 values for chlorosilanes is moderate, reflecting the
limited data on AEGL-2 end points after chlorosilane exposure and reliance on
HCl data. Additional research on AEGL-2 effects of chlorosilanes would reduce
uncertainty.
AEGL-2 VALUES FOR DICHLOROSILANES
10 min 30 min 1h 4h 8h
50 ppm 22 ppm 11 ppm 5.5 ppm 5.5 ppm
Key reference: NRC (National Research Council). 2004. Hydrogen chloride.
Pp. 77-122 in Acute Exposure Guideline Levels for Selected Airborne
Chemicals, Vol. 4. Washington, DC: National Academies Press.
End point/Concentration/Rationale: AEGL-2 values for dichlorosilanes were
derived by adjusting the AEGL-2 values for HCl by the molar ratio of HCl to
dichlorosilane. This approach is considered reasonable because qualitative and
quantitative data on chlorosilanes suggest that the HCl hydrolysis product is
largely responsible for the acute toxicity of the chlorosilanes.
Molar adjustment factor: 2
Data adequacy: Mechanism-of-action data were considered adequate for
the derivation of AEGL-2 values for chlorosilanes based on analogy to HCl.
Confidence in the AEGL-2 values for chlorosilanes is moderate, reflecting
the limited data on AEGL-2 end points after chlorosilane exposure and reliance
on HCl data. Additional research on AEGL-2 effects of chlorosilanes would
reduce uncertainty.
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158 Acute Exposure Guideline Levels
AEGL-2 VALUES FOR TRICHLOROSILANES
10 min 30 min 1h 4h 8h
33 ppm 14 ppm 7.3 ppm 3.7 ppm 3.7 ppm
Key reference: NRC (National Research Council). 2004. Hydrogen chloride.
Pp. 77-122 in Acute Exposure Guideline Levels for Selected Airborne
Chemicals, Vol. 4. Washington, DC: National Academies Press.
End point/Concentration/Rationale: AEGL-2 values for trichlorosilanes were
derived by adjusting the AEGL-2 values for HCl by the molar ratio of HCl to
trichlorosilane. This approach is considered reasonable because qualitative and
quantitative data on chlorosilanes suggest that the HCl hydrolysis product is
largely responsible for the acute toxicity of the chlorosilanes.
Molar adjustment factor: 3
Data adequacy: Mechanism-of-action data were considered adequate for
the derivation of AEGL-2 values for chlorosilanes based on analogy to HCl.
Confidence in the AEGL-2 values for chlorosilanes is moderate, reflecting
the limited data on AEGL-2 end points after chlorosilane exposure and reliance
on HCl data. Additional research on AEGL-2 effects of chlorosilanes would
reduce uncertainty.
AEGL-2 VALUES FOR TETRACHLOROSILANE
10 min 30 min 1h 4h 8h
25 ppm 11 ppm 5.5 ppm 2.8 ppm 2.8 ppm
Key reference: NRC (National Research Council). 2004. Hydrogen chloride.
Pp. 77-122 in Acute Exposure Guideline Levels for Selected Airborne
Chemicals, Vol. 4. Washington, DC: National Academies Press.
End point/Concentration/Rationale: AEGL-2 values for tetrachlorosilane were
derived by adjusting the AEGL-2 values for HCl by the molar ratio of HCl to
tetrachlorosilane. This approach is considered reasonable because qualitative
and quantitative data on chlorosilanes suggest that the HCl hydrolysis product
is largely responsible for the acute toxicity of the chlorosilanes.
Molar adjustment factor: 4
Data adequacy: Mechanism-of-action data were considered adequate for
the derivation of AEGL-2 values for chlorosilanes based on analogy to HCl.
Confidence in the AEGL-2 values for chlorosilanes is moderate, reflecting
the limited data on AEGL-2 end points after chlorosilane exposure and reliance
on HCl data. Additional research on AEGL-2 effects of chlorosilanes would
reduce uncertainty.
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159
Selected Chlorosilanes
AEGL-3 VALUES FOR MONOCHLOROSILANES
10 min 30 min 1h 4h 8h
620 ppm 210 ppm 100 ppm 26 ppm 26 ppm
Key reference: NRC (National Research Council). 2004. Hydrogen chloride. Pp.
77-122 in Acute Exposure Guideline Levels for Selected Airborne Chemicals,
Vol. 4. Washington, DC: National Academies Press..
End point/Concentration/Rationale: AEGL-3 values for HCl were adopted
as AEGL-3 values for monochlorosilanes. This approach is considered
reasonable because qualitative and quantitative data on chlorosilanes
suggest that the HCl hydrolysis product is largely responsible for the
acute toxicity of the chlorosilanes.
Data adequacy: Data were considered adequate for the derivation of AEGL-3
values for chlorosilanes based on analogy to HCl. Confidence in the AEGL-3
values for chlorosilanes is high, reflecting the availability of lethality data on
11 of the 26 chlorosilanes considered and evidence for the role of HCl as the
proximate toxicant. No additional research is needed on AEGL-3 end points.
AEGL-3 VALUES FOR DICHLOROSILANES
10 min 30 min 1h 4h 8h
310 ppm 110 ppm 50 ppm 13 ppm 13 ppm
Key reference: NRC (National Research Council). 2004. Hydrogen chloride.
Pp. 77-122 in Acute Exposure Guideline Levels for Selected Airborne
Chemicals, Vol. 4. Washington, DC: National Academies Press.
End point/Concentration/Rationale: AEGL-3 values for dichlorosilanes were
derived by adjusting the AEGL-3 values for HCl by the molar ratio of HCl to
dichlorosilane. This approach is considered reasonable because qualitative and
quantitative data on chlorosilanes suggest that the HCl hydrolysis product is
largely responsible for the acute toxicity of the chlorosilanes.
Molar adjustment factor: 2
Data adequacy: Data were considered adequate for the derivation of AEGL-3
values for chlorosilanes based on analogy to HCl. Confidence in the AEGL-3
values for chlorosilanes is high, reflecting the availability of lethality data on 11
of the 26 chlorosilanes considered and evidence for the role of HCl as the
proximate toxicant. No additional research is needed on AEGL-3 end points.
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160 Acute Exposure Guideline Levels
AEGL-3 VALUES FOR TRICHLOROSILANES
10 min 30 min 1h 4h 8h
210 ppm 70 ppm 33 ppm 8.7 ppm 8.7 ppm
Key reference: NRC (National Research Council). 2004. Hydrogen chloride.
Pp. 77-122 in Acute Exposure Guideline Levels for Selected Airborne
Chemicals, Vol. 4. Washington, DC: National Academies Press.
End point/Concentration/Rationale: AEGL-3 values for trichlorosilanes were
derived by adjusting the AEGL-3 values for HCl by the molar ratio of HCl to
trichlorosilane. This approach is considered reasonable because qualitative
and quantitative data on chlorosilanes suggest that the HCl hydrolysis product
is largely responsible for the acute toxicity of the chlorosilanes.
Molar adjustment factor: 3
Data adequacy: Data were considered adequate for the derivation of AEGL-3
values for chlorosilanes based on analogy to HCl. Confidence in the AEGL-3
values for chlorosilanes is high, reflecting the availability of lethality data on 11
of the 26 chlorosilanes considered and evidence for the role of HCl as the
proximate toxicant. No additional research is needed on AEGL-3 end points.
AEGL-3 VALUES FOR TETRACHLOROSILANE
10 min 30 min 1h 4h 8h
160 ppm 53 ppm 25 ppm 6.5 ppm 6.5 ppm
Key reference: NRC (National Research Council). 2004. Hydrogen chloride.
Pp. 77-122 in Acute Exposure Guideline Levels for Selected Airborne
Chemicals, Vol. 4. Washington, DC: National Academies Press.
End point/Concentration/Rationale: AEGL-3 values for tetrachlorosilane were
derived by adjusting the AEGL-3 values for HCl by the molar ratio of HCl to
tetrachlorosilane. This approach is considered reasonable because qualitative
and quantitative data on chlorosilanes suggest that the HCl hydrolysis product is
largely responsible for the acute toxicity of the chlorosilanes.
Molar adjustment factor: 4
Data adequacy: Data were considered adequate for the derivation of AEGL-3
values for chlorosilanes based on analogy to HCl. Confidence in the AEGL-3
values for chlorosilanes is high, reflecting the availability of lethality data on
11 of the 26 chlorosilanes considered and evidence for the role of HCl as the
proximate toxicant. No additional research is needed on AEGL-3 end points.
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161
Selected Chlorosilanes
APPENDIX E
DERIVATION SUMMARY TABLES FOR HYDROGEN CHLORIDE
(Excerpted from NRC 2004)
Derivation Summary
AEGL-1 VALUES FOR HYDROGEN CHLORIDE
10 min 30 min 1h 4h 8h
1.8 ppm 1.8 ppm 1.8 ppm 1.8 ppm 1.8 ppm
Key reference: Stevens, B., J.Q. Koenig, V. Rebolledo, Q.S. Hanley, and D.S.
Covert, D.S. 1992. Respiratory effects from the inhalation of hydrogen chloride
in young adults with asthma. J. Occup. Med. 34(9): 923-929.
Test species/Strain/Number: Human adults with asthma, 10
Exposure route/Concentrations/Durations: Inhalation at 0, 0.8, or 1.8 ppm for
45 min while exercising (1.8 ppm was determinant for AEGL-1)
Effects: No treatment-related effects were observed in any of the individuals tested
End point/Concentration/Rationale: The highest concentration tested was a
no-effect level for irritation in a sensitive human population (10 asthmatic
individuals tested) and was selected as the basis of AEGL-1. Effects assessed
included sore throat, nasal discharge, cough, chest pain or burning, dyspnea,
wheezing, fatigue, headache, unusual taste or smell, total respiratory resistance,
thoracic gas volume at functional residual capacity, forced expiratory volume,
and forced vital capacity. All subjects continued the requisite exercise routine
for the duration of the test period.
Uncertainty factors/Rationale:
Total uncertainty factor:
Interspecies: 1, test subjects were human
Intraspecies: 1, test subjects were sensitive population (exercising
asthmatic subjects)
Modifying factor: Not applicable
Animal-to-human dosimetric adjustment: Insufficient data
Time-scaling: The AEGL-1 values for a sensory irritant were held constant
across time because it is a threshold effect and prolonged exposure will not
result in an enhanced effect. In fact one might become desensitized to the
respiratory-tract irritant over time. Also, this approach was considered valid
since the end point (no treatment-related effects at the highest concentration
tested in exercising asthmatic subjects) is inherently conservative.
Data quality and research needs: The key study was well-conducted in a sensitive
human population and is based on no treatment-related effects. Additionally, the
direct-acting irritation response is not expected to vary greatly among individuals.
Therefore, confidence in the AEGL values is high.
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162 Acute Exposure Guideline Levels
AEGL-2 VALUES FOR HYDROGEN CHLORIDE
10 min 30 min 1h 4h 8h
100 ppm 43 ppm 22 ppm 11 ppm 11 ppm
Key references: Stavert, D.M., D.C. Archuleta, M.F. Behr, and B.E. Lehnert.
1991. Relative acute toxicities of hydrogen chloride, hydrogen fluoride, and
hydrogen bromide in nose- and pseudo-mouth-breathing rats. Fundam. Appl.
Toxicol. 16(4):636-655. (30-, 1-, 4-min and 8-h AEGLs)
Barrow, C.S., Y. Alarie, M. Warrick, and M.F. Stock. 1977. Comparison of
the sensory irritation response in mice to chlorine and hydrogen chloride. Arch.
Environ. Health 32(2):68-76. (10-min AEGL)
Test species/Strain/Number: F344 rats, 8 males/concentration (30-min, 1-, 4-,
and 8-h); Male Swiss Webster mice (10-min)
Exposure route/Concentrations/Durations: inhalation at 0 or 1,300 ppm for
30 min (1,300 ppm was determinant for 30-min, 1-, 4-, and 8-h AEGL-2)
Effects (30-min, 1-, 4-, and 8-h): 0 ppm, no effects; 1,300 ppm, severe
necrotizing rhinitis, turbinate necrosis, thrombosis of nasal submucosa vessels
in nose-breathers; 1,300 ppm, severe ulcerative tracheitis accompanied by
necrosis and luminal ulceration in mouth-breathers (determinant for AEGL-2);
RD50 = 309 ppm (determinant for 10-min AEGL-2)
End point/Concentration/Rationale: 1,300 ppm for 30 min; severe lung effects
(ulcerative tracheitis accompanied by necrosis and luminal ulceration) or nasal
effects (necrotizing rhinitis, turbinate necrosis, thrombosis of nasal submucosa
vessels histopathology) in pseudo-mouth breathing male F344 rats (30-min,
1-, 4-, and 8-h); RD50 of 309 ppm ÷ 3 to estimate irritation (10-min)
Uncertainty Factors/Rationale (30-min, 1-, 4-, and 8-h):
Total uncertainty factor: 10
Intraspecies: 3, steep concentration-response curve implies limited
individual variability.
Interspecies: 3, use of an intraspecies uncertainty factor of 10 would bring the
total uncertainty/modifying factor to 100 instead of 30. That would generate
AEGL-2 values that are not supported by data on exercising asthmatic subjects,
an especially sensitive subpopulation because exercise increases HCl uptake and
exacerbates irritation. No effects were noted in exercising young adult with asthma
exposed to HCl at 1.8 ppm for 45 min (Stevens et al. 1992). Using a total
uncertainty factor of 30 would yield 4- and 8-h values of 3.6 ppm (instead of 11
ppm). It is not supportable to predict that humans would be disabled by exposure
at 3.6 ppm for 4- or 8-h when exercising asthmatic subjects exposed to one-half
this level for 45 min had no effects. The shorter time points would yield values
4- to 7 times above 1.8 ppm; however, the confidence in the time scaling for HCl
is good for times up to 100 min because the value of n value was derived from a
regression analysis of rat and mouse mortality data with exposure durations
ranging from 1 min to 100 min. The 30-min value of 43 ppm derived with the total
uncertainty factor of 10 is reasonable in light of the fact that baboons exposed to
500 ppm for 15 min experienced only a slightly increased respiratory rate.
(Continued)
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163
Selected Chlorosilanes
AEGL-2 VALUES FOR HYDROGEN CHLORIDE Continued
10 min 30 min 1h 4h 8h
100 ppm 43 ppm 22 ppm 11 ppm 11 ppm
Modifying factor:
30-min, 1-, 4-, and 8-h AEGLs: 3 based on sparse database for AEGL-2 effects
and that the effects observed at the concentration used as the basis for AEGL-2
values were somewhat severe.
10-min AEGL-2: the 10-min AEGL-2 value was derived by dividing the mouse
RD50 of 309 ppm by a factor of 3 to obtain a concentration causing irritation
(Barrow et al. 1977). One-third of the mouse RD50 for HCl corresponds to an
approximate decrease in respiratory rate of 30%, and decreases in the range of
20% to 50% correspond to moderate irritation (ASTM 1991).
Animal-to-human dosimetric adjustment: Insufficient data
Time-scaling: Cn × t = k, where n=1, based on regression analysis of combined
rat and mouse LC50 data (1 min to 100 min) reported by ten Berge et al. (1986).
Data point used to derive AEGL-2 was 30 min. AEGL-2 values for 1-h exposure
period was based on extrapolation from the 30-min value. The 4- and 8-h
AEGL-2 values were derived by applying a modifying factor of 2 to the 1-h
AEGL-2 value because time scaling would yield a 4-h AEGL-2 value of
5.4 ppm and an 8-h AEGL-2 of 2.7 ppm, close to the 1.8 ppm tolerated by
exercising asthmatic subjects without adverse health effects.
Data quality and research needs: Confidence is moderate since the species used
is more sensitive than primates to the effects of HCl, the chemical is a direct-
acting irritant, and a modifying factor was included to account for the relative
severity of effects and sparse data base.
AEGL-3 VALUES FOR HYDROGEN CHLORIDE
10 min 30 min 1h 4h 8h
620 ppm 210 ppm 100 ppm 26 ppm 26 ppm
Key reference: Vernot, E.H., J.D. MacEwen, C.C. Haun, and E.R. Kinkead.
1977. Acute toxicity and skin corrosion data for some organic and inorganic
compounds and aqueous solutions. Toxicol. Appl. Pharmacol. 42(2):417-423.
Wohlslagel, J., L.C. DiPasquale, and E.H. Vernot. 1976. Toxicity of solid
rocket motor exhaust: Effects of HCl, HF, and alumina on rodents. J.
Combust. Toxicol. 3:61-69.
Test species/Strain/Sex/Number: Sprague-Dawley rats, 10 males per concentration
Exposure route/Concentrations/Durations: inhalation at 0, 1,813, 2,585, 3,274,
3,941, or 4,455 ppm for 1 h
(Continued)
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164 Acute Exposure Guideline Levels
AEGL-3 VALUES FOR HYDROGEN CHLORIDE Continued
10 min 30 min 1h 4h 8h
620 ppm 210 ppm 100 ppm 26 ppm 26 ppm
Effects: Concentration Mortality
0 ppm 0/10
1,813 ppm 0/10
2,585 ppm 2/10
3,274 ppm 6/10
3,941 ppm 8/10
4,455 ppm 10/10
LC50: reported as 3,124 ppm (determinant for AEGL-3)
End point/Concentration/Rationale: One-third of the 1-h LC50 (3,124 × 1/3 =
1,041 ppm) to estimate a concentration causing no deaths.
Uncertainty factors/Rationale:
Total uncertainty factor: 10
Intraspecies: 3, a steep concentration-response curve implies limited individual
variability.
Interspecies: 3, (1) the steep concentration-response curve for lethality observed
in the Wohlslagel et al. (1976) study in which 1,041 ppm (one-third of the LC50
of 3,124 ppm) was lower than the LC0 of 1,813 ppm. This is a conservative
selection of the LC0 and the steep concentration-response curve argues for little
interindividual variability; (2)AEGL-3 values generated from a total uncertainty
factor of 30 would be close to the AEGL-2 values (within a factor of 2) generated
above which are reasonable when compared with data on exercising asthmatic
subjects; (3) Sellakumar et al. (1985) exposed rats to 10 ppm of HCl for 6 h/day,
5 days/week for life and only observed increased trachael and laryngeal
hyperplasia. The estimated 6-h AEGL-3 using an intraspecies uncertainty factor
of 3 is 17 ppm, close to the level used in the lifetime study in which only mild
effects were induced; and (4) rats exposed at 50 ppm for 6 h/day, 5 days/week
for 90 days exhibited mild rhinitis (Toxigenics Inc. 1984). This level is already 2
times that of the AEGL-3 value for death. Thus, the total uncertainty factor is 10.
Modifying factor: Not applicable
Animal-to-human dosimetric adjustment: Insufficient data
Time-scaling: Cn × t = k, where n = 1, based on regression analysis of rat and
mouse mortality data (1 min to 100 min) reported by ten Berge et al. (1986).
Reported 1-h data point was used to derive AEGL-3 values. AEGL-3 values for
10-min, 30-min, and 4-h were based on extrapolation from the 1-h value. The
4-h value was adopted as the 8-h value.
Data quality and research needs: Study is considered appropriate for AEGL-3
derivation because exposures are over a wide range of HCl concentrations and
utilize a sufficient number of animals. Data were insufficient to derive a no-effect
level for death. One-third of the LC50 has been utilized previously for chemicals
with steep concentration-response curves. Also, in the key study, no deaths were
observed in rats exposed at 1,813 ppm.
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165
Selected Chlorosilanes
APPENDIX F
CATEGORY PLOTS FOR SELECTED CHLOROSILANES
Chemical Toxicity - Rat LC50 Data
Monochlorosilanes*
10000
Human - No Effect
Human - Discomfort
1000 Human - Disabling
Animal - No Effect
ppm
100 Animal - Discomfort
AEGL-3
Animal - Disabling
AEGL-2
10 Animal - Partially Lethal
Animal - Lethal
AEGL-1
AEGL
1
0 60 120 180 240 300 360 420 480
Minutes
FIGURE F-1 Category plot for monochlorosilanes. *Data plotted are for trimethyl chlo-
rosilane and dimethyl chlorosilane.
Chemical Toxicity - Rat LC50 Data
Dichlorosilanes*
10000
Human - No Effect
Human - Discomfort
1000
Human - Disabling
Animal - No Effect
100
ppm
Animal - Discomfort
AEGL-3
10
Animal - Disabling
AEGL-2
Animal - Partially Lethal
1
AEGL-1
Animal - Lethal
AEGL
0
0 60 120 180 240 300 360 420 480
Minutes
FIGURE F-2 Category plat of dichlorosilanes. *Data plotted are for methylvinyl dichlo-
rosilane, dimethyl dichlorosilane, and methyl dichlorosilane.
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166 Acute Exposure Guideline Levels
Chemical Toxicity - Rat LC50 Data
Trichlorosilanes*
10000
Human - No Effect
Human - Discomfort
1000
Human - Disabling
Animal - No Effect
100
ppm
Animal - Discomfort
AEGL-3
10
Animal - Disabling
AEGL-2
Animal - Partially Lethal
AEGL-1
1
Animal - Lethal
AEGL
0
0 60 120 180 240 300 360 420 480
Minutes
FIGURE F-3 Category plot for trichlorosilanes. *Data plotted are for propyl trichlorosi-
lane, vinyl trichlorosilane, methyl trichlorosilane, and ethyl trichlorosilane.
Chemical Toxicity - Rat Lethality Data
Tetrachlorosilane
10000
Human - No Effect
Human - Discomfort
1000
Human - Disabling
Animal - No Effect
100
ppm
Animal - Discomfort
AEGL-3
10
Animal - Disabling
AEGL-2
Animal - Partially Lethal
1
Animal - Lethal
AEGL-1
AEGL
0
0 60 120 180 240 300 360 420 480
Minutes
FIGURE F-4 Category plot for tetrachlorosilane.
