4
OEC 20
RE: WCBCJ0411
NON-CONFIDENTIAL BUSINESS INFORMATION
LISTING BACKGROUND DOCUMENT
1,1-DIMETHYLHYDRAZINE (UDMH) PRODUCTION FROM CARBOXYLIC
ACID HYDRAZIDES
K107 Column bottoms from product separation in the manufacture
of UDMH (1,1-dimethylhydrazine) using carboxylic acid
hydrazides (C,T)
K108 Condensed column overheads from product separation and
condensed reactor vent gases in the manufacture of UDMH
(1,1-dimethylhydrazine) using carboxylic acid hydrazides (T)
K109 Spent filter cartridges from product purification
manufacture of UDMH ( 1 ,1-dimethylhydrazine) using
acid hydrazides (T)
in the
carboxylic
KllO Condensed column overheads from intermediate separtion in
the manufacture of UDMH (1,1-dimethylhydrazine) using
carboxylic acid hydrazides (I,T)
MAR
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28073
TABLE OF CONTENTS
:" 2 0 /OP/I
I. SUMMARY OF BASIS FOR LISTING 3
II. SOURCES OF WASTE AND TYPICAL DISPOSAL PRACTICES 4
A. Industry Profile 4
B. Manufacturing Process 4
C. Waste Generation and Management 5
D. Waste Composition 8
III. BASIS FOR LISTING 10
A. Hazards Posed by the Listed Wastes
and Wastes Contituents 10
B. Potential for Mismangement 10
C. Environmental Fate and Transport; Migration,
Mobility, and Persistence 11
D. Health Effects 13
E. Existing Regulations and Guidelines 15
IV. REFERENCES 18
ENVIRONMENTAL
PROTECTION AGENCY
REGION 9
MAR 1 'A 1985
LIBRARY
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I. SUMMARY OF BASIS FOR LISTING
20 /
The unique proprietary manufacturing process to produce
1,1-dimethylhydrazine (UDMH) by Uniroyal, Inc. generates four
liquid wastes containing hazardous concentrations of UDMH and in
some cases methanol, ethanol, and sodium hydroxide. These wastes
are all toxic, and in some cases ignitable or corrosive. The
Administrator has determined that these wastes are solid wastes
that may pose a substantial present or potential hazard to human
health or the environment when improperly treated, stored, disposed
of, or otherwise managed, and therefore should be subject to
appropriate management requirements under Subtitle C of RCRA.
This conclusion is based on the following considerations:
1. These wastes contain significant concentrations
of 1,1-dimethylhydrazine (unsymmetrical dimethyl-
hydrazine, UDMH), which has been determined by the
U.S. EPA1s Carcinogen Assessment Group (CAG) to
be a potential human carcinogen.
2. The condensed column overheads from product separation
and condensed reactor vent gases also contain significant
concentrations of alcohols, making this waste ignitable.
The column bottoms from product separation contain
significant concentrations of sodium hydroxide, making
this waste corrosive.
3. A significant volume of these wastes (5000 metric tons
or 11 million pounds) are generated annually, increasing
the opportunity for hazardous exposures if mismanagement
occurs.
4. UDMH is mobile and persistent in ground water under
conditions approximating waste disposal. Therefore,
ground water contamination is possible under
conditions approximating waste disposal if deep well
injection techniques (the current disposal practice for
the purification column light ends and bottoms) are
improperly conducted or if the wastes are mismanaged
during storage or disposal in unlined or inadequately
lined land disposal facilities.
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II. SOURCES OF WASTE AND TYPICAL DISPOSAL PRACTICES
A. Industry Profile
1,1-Dimethylhydrazine, commonly known as unsymmetrical
dimethylhydrazine (UDMH), is manufactured via a unique proprietary
process by Uniroyal, Inc. This UDMH product is presently not
marketed commercially but is produced solely as an intermediate
for Uniroyal products. Current production figures are unavailable.
The Olin Corporation also manufactures UDMH by a different
chemical process than that employed by Uniroyal. This process
will be evaluated separately because the process chemistry involved
is expected to yield wastes with different characteristics.
Olin's product is sold commercially, and finds use as a rocket
fuel, and to a smaller extent, as an absorbent for acid gases, in
the manufacture of various photographic chemicals, and as a stabilizer
for organic peroxide fuel additives. Another use for Olin's product
is as an analytical reagent for aldehyde and ketone analysis.
B. Manufacturing Process
A complete description of the Uniroyal manufacturing process
and process chemistry, provided by the manufacturer in response
to a questionnaire under Section 3007 of the Resource Conservation
and Recovery Act (RCRA), has been claimed to be confidential
business information by Uniroyal, and therefore is not presented
here. Readily available information in the technical literature
(Kirk-Othmer), however, states that UDMH is probably made (by
Uniroyal) by the reductive catalytic alkylation of a carboxylic
acid hydrazide with formaldehyde and hydrogen, followed by
basic hydrolysis of carboxylic acid dimethylhydrazide to
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remove the carboxyl group, as shown in the following equation.
CH20/H20 base
RCONHNH2 > RCONHN(CH3)2 > (CH3)2NNH2
Figure 1 shows this conversion with the associated waste and
process streams. Triangles indicate streams in the gaseous state,
while circles indicate streams in the liquid state and squares
represent wastes in the solid state. This figure has been
generalized so as to protect confidential process information.
C. Waste Generation and Management
There are three liquid waste streams and one solid waste
stream generated by this process, described below and keyed to
Figure 1.
The primary waste that is generated is the column
bottoms from the final purification step to produce commercial
UDMH (Liquid Stream 4, Waste No. K107). This waste is
currently managed by injection in a 3000 ft. deep well on
the plant premise after holding in a concrete-lined surface
impoundment. Approximately 2,810 metric tons of this waste
are generated annually. Sludges are accumulated in the
concrete-lined surface impoundment* from holding the product
purification bottoms along with other wastes from Uniroyal's
facility.
* Uniroyal has indicated they will incinerate these sludges
pending completion of an on-site incinerator.
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9Q
a* i
The second listed waste is the condensed overheads from a
combination of reactor vent gases (Gas Stream 1) and product
separation vent gases (Gas Stream 2), which are co-condensed to
generate a liquid waste (Liquid Stream 1+2, Waste No. K108).
This waste is incinerated off-site or injected in a deep
well off-site. Approximately 91 metric tons of this waste
are generated anually.
The third listed waste is spent filter cartridges from
product purification (Solid Stream 8, Waste No. K109).
This residual has not yet required removal and disposal. At
the time when disposal is required, the company plans to use a
permitted hazardous waste diposal facility. The quantity of
this waste is judged to be small, since only a small fraction
of the facility's UDMH is passed through filter cartridges.
The fourth listed waste is condensed overheads from
intermediate separation columns (Liquid Stream 3, Waste No. K110)
which is codisposed with the product separation column
bottoms (Stream 4, Waste No. K107) in the surface impoundment,
prior to deep well injection on-site.
The uncondensed fractions of Gas Streams 1, 2 and 3 are
flared at Gas Stream 5.
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FEEDSTOCK
^
w
REACTORS
FIGURE 1; PROCESS FLOW DIAGRAM,
UDMH BY THE UNIRQYAL PROCESS
SEPARATION
COLIMNS
PROFXCT
CONDENSATION
STEPS
FIARE
r
INCINERATOR |
I
©
Waste #107
RtJRFACE
IMPODNHMENT
I
| OTHER PLANT
I
I
DERP WELL |
I INTECTTON
I
SPEOT FILTER
CARTRIDGE
Waste
triangles = gaseous streams
circles = liquid streams .
squares = solid streams
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D. Waste Composition L^S £.£ fi\ Em j
Table 1 shows the approximate concentrations of the toxicant
of concern in the wastes generated by Uniroyal's proprietary UDMH
process, along with the volume generated.
The bottoms from the product separation column (Waste
No. K107) contain approximately 0.01 per cent (100 ppm) of
UDMH, according to information supplied by Uniroyal. This
waste is also corrosive, due to high sodium hydroxide content.
The condensed overheads from product separation and
condensed reactor vent gases (Waste No. K108) contain
1-10 per cent (10,000 to 100,000 -ppm) of UDMH, according to
company supplied information.
The spent filter cartridges from products purification
(Waste No. K109) are estimated by the Agency to contain'40-50
per cent (400,000 to 500,000 ppm) of UDMH. This is based on
the concentrations of similar liquids entrained in filter
cartridges through which they are passes.
The condensed intermediate separation column overheads
(Waste No. K110) have the possibilty of being contaminated with
traces of UDMH at some time, according to Uniroyal, and are therefore
handled as hazardous by Uniroyal because of this possibility.
This waste also contains sufficient concentrations of alcohols to
create an ignitable mixture.
Bottom sediment sludges from the concrete-lined surface
impoundment are derived from two listed wastes, Waste No. K107
and K110, and, therefore are also defined as a hazardous
waste by 40 CFR § 261.3(c)(2). These sludges could contain
significant concentrations of UDMH, as well as toxic waste
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Table 1. SUMMARY OF UDMH CONCENTRATIONS IN WASTES & WASTE VOLUME DATA
FROM THE PRODUCTION OF UDMH FROM CARBOXYLIC ACID HYDRAZIDES
(Reference: Industry Studies 3007 Data Base questionnaire)
Waste No.
K109
K110
Description
Concentrat ions*
Total Estimated
(metric tons)
K107
K108
Column bottoms from product
separation
Condensed column overheads
approx imately
0.01%
1-10%
2,810
91
from product separation and
condensed reactor vent gases.
Spent filter cartridges
from product purification
Condensed column overheads
from intermediate separation
40-50%
trace to 0.01%
not yet generated
1,250
Hazardous constituent for which the wastes are listed. There is insufficient data to
make an accurate determination of the presence of other compounds which should be
considered hazardous constituents. If such data becomes available in the future, at
that point the may be listed as additional hazardous constituents.
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constituents from other processes on the Uniroyal facility.
Ill. BASIS FOR LISTING
A. Hazards Posed by^ the Listed Wastes and Wastes Contituents
UDMH is capable of migrating from listed wastes, is mobile
and persistant in the environment, and in situations similar
to waste mismanagement it may reach environmental receptors,
posing a risk to human health and the environment. The following
summarizes experimental information on the environmental fate
and transport and health effects of UDMH. More detailed
information is available in the Health and Environmental
Effects Profile (HEEP) for UDMH.
UDMH is present in these wastes in significant concentrations,
typically in concentrations many orders or magnitude above the
levels related to the adverse health effects described in the following
section. For example, if the condensed column overheads from
product separation (the least contaminated waste) were contaminated
with even one part per million UDMH, then the concentration would
approach one million times the levels related to human health
risks in drinking water. The concentration of UDMH in drinking
water ingested over a lifetime resulting in a one per million
increased risk of cancer is 4.03 x 10~6 milligrams per liter
(parts per million), or 4.03 x 10~10 percent.
B. Potential for Mismangement
The high mobility and migratory potential of the
wastes (UDMH and the solvent alcohols in these wastes are
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miscible with water) increases the likelihood of harmful
exposures under conditions typical of waste management scenarios.
Only a fraction of the toxicants present in these wastes need
migrate and reach environmental receptors to pose the potential
for substantial harm if these wastes are managed improperly.
For example, storage or treatment of these wastes in an unlined
surface impoundment could lead to sterilization of the
microbial population and the formation of anaerobic conditions
beneath the surface impoundment. This could prevent degradation
or oxidation of UDMH and allow sufficient quantities to migrate
and contaminate ground water. Improper deep well injection could
similarly contaminate ground water.
Other examples of potential waste mismanagement practices
leading to hazardous exposures could be inadequate incineration
or disposal or storage in impoundments or tanks with large open
surface areas such that significant volatilization of UDMH
occurs.
C. Environmental Fate and Transport; Migration, Mobility,
and Persistence.
UDMH is soluble in water in all proportions (miscible) (U.S.
EPA, 1980-1984) and is present in wastes which are liquids. The
UDMH in these wastes thus has a high mobility and migratory
potential. In addition, under conditions typical of waste
mismanagement, UDMH is persistent enough to cause harmful exposures.
Only a fraction of the toxicant present in these wastes need
migrate and reach environmental receptors to pose the potential
for substantial harm.
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UDMH's low octanol-water partition coefficient and complete
miscibility with water indicate that UDMH in any waste contacting
soil may migrate and contaminate ground water without being
adsorbed onto the soil matrix. UDMH has been shown to leach and
migrate in experimental soil columns (Braun, 1983).
The primary degradation mechanism of UDMH in the unsaturated
soil zone or aerated surface waters is expected to be oxidation,
presumably with dissolved oxygen and free radicals. In the absence
of microbial degradation, the hal^-life of UDMH was reported to be
10 to 14 days in ponds and seawaters (Zirrolli, 1983). In
anaerobic conditions, such as in ground water, however, UDMH has
the potential for persisting for much longer periods. UDMH was
found to be extremely stable in distilled water (Braun, 1983).
The potential for aerobic biodegradation of UDMH in water
has not been explored thoroughly, but may be minor relative to
oxidation under neutral to basic conditions. UDMH oxidation was
found to proceed at the same rate in sterile or non-sterile lake
water as well as in pure distilled water (Banerjee; 1977, 1981).
Under anaerobic conditions, the loss of UDMH with anaerobic bacteria
was 26% after a six-day bioassay. Biodegradation of UDMH may also
be limited by its toxicity; aerobic bacterial degradation was
inhibited when UDMH concentrations were as low as 20 parts per million
(Kane, 1983).
UDMH could also be released to the atmosphere by evaporation from
spills, leaks and venting during loading, transfer, storage, or
treatment. Evaporation of UDMH from water solutions are expected to
be significant (MacNaughton, 1975; Stauffer, 1977). Once volatilized,
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UDMH may degrade by reaction with hydroxyl radicals (Pitts, 1981),
NC>2 or ozone (Tuazon, 1982).
1,1-Dimethylnitrosamine is a potential degradation product
of UDMH in the environment, and has also been determined by
the U.S. CAG to be a potential .human carcinogen.* A major
product of the reaction of UDMH with ozone (Tuazon, 1982); however,
1,1-dimethylnitrosamine appears to degrade rapidly in the atmosphere
by sunlight (Hanst, 1977; Callahan, 1979; Tuazon, 1982). The forma-
tion of 1,1-dimethylnitrosamine may also result from the oxidation
of concentrated aqueous solutions of UDMH (Banerjee, 1981), such
as would result from spills. The.subsequent environmental
degradation of 1,1-dimethylnitrosamine is expected to be signifi-
cantly longer than that of UDMH in water and soil (Tate, 1975;
Callahan, 1979; Oliver, 1979; Mallik, 1981).
D. Health Effects
The primary concern of the Agency for the hazardous nature
of these wastes is their contamination by significant concentrations
of 1,1-dimethylhydrazine (UDMH), which is currently listed in
Appendix VIII of Part 261. The U.S. EPA's Carcinogen Assessment
Group (CAG) has determined that UDMH is a potential human carcinogen.
In addition, N-nitrosodimethylamine (dimethylnitrosamine) is a
potential degradation product of volatilized UDMH,* and also has
been determined by CAG as a potential human carcinogen.
The major contaminant of concern in these wastes, UDMH,
The Agency is not listing 1,1-dimethylnitrosamine as a toxicant
of concern because of uncertainty of the potential degradation
pathways of UDMH in the environment. However, the Agency solicits
comments as to whether or not 1,1-dimethylnitrosamine should be
included as a toxicant of concern.
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is currently listed in Appendix VIII of Part 261.
When UDMH was administered orally, it produced angiosarcomas,
pulmonary adenomas or adenocarcinomas, malignant lymphomas, and
kidney adenomas in male and female Swiss mice (Toth, 1972, 1973);
tumors in the cecum and blood i'n Syrian golden hamsters (Toth,
1977); lung tumors in female Swiss mice (Roe e_t al . , 1967); and
liver tumors in rats (Druckrey e_t _al.f 1967).
UDMH is also teratogenic and mutagenic. Teratogenic effects
were observed in South African clawed toad larvae, xenopus laevis,
following continuous embronic exposure to UDMH concentrations of
2-20 ug/1 (Greenhouse, 1976). UDMH was teratogenic during the
neurulation period of embryogenesis, and the malformations affected
the head, trunk and tail; the most frequent malformation was tail
kinks .
The overall weight of evidence from a variety of microbial
and mammalian assays indicates that UDMH is also mutugenic. In
numerous Ames Salmonella assays, results were generally inconsistent,
although most positive reponses were observed with strain TA98, a
frameshift mutant (Bruce, 1979; Parodi et_ a±. , 1981; de Flora,
1981). In mutagenesis assays with cultured mouse lymphoma cells,
UDMH caused forward mutation to thymidine (Brusick, 1976; Rogers,
1981), but not to ouabain, thioguanine or cytosine arabinoside
resistance (Rogers, 1981). Unscheduled DNA synthesis occurred in
human embryonic lung cells that were treated with UDMH ^n vitro
(Brusick, 1976), and ir\ vivo exposure to UDMH inhibited testicular
DNA synthesis in mice (Seiler, 1977). Ijn vivo treatment of mice
also caused DNA fragmentation in liver and lung cells (Parodi,
1981), but did not induce micronuclei in bone marrow cells (Bruce,
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1979) or sperm abnormalities (Bruce, 1979; Wyrobek, 1975).
UDMH is rapidly absorbed from the lungs, gastrointestinal
tract, injection sites, and skin. Rats exposed to UDMH had grand
mal seizures, brain glycogen degradation, and inhibition of
glutamic acid decarboxylase (U.S.EPA, 1984).
The Agency has made a preliminary estimate that persons
face a 1 per million increased risk of cancer as a result of
a lifetime daily dose of 1.15 x 10~7 milligrams UDMH per
kilogram body weight, or 8.05 x 10~6 milligrams for a 70
kilogram man. The basis for this- estimate is explained
further in the HEEP. The corresponding concentration in drinking
water ingested over a lifetime resulting in a one per million
increased risk of cancer is 4.03 x 10~6 milligrams per liter
(parts per million), or 4.03 x 10~10 percent.
The potential of this contaminant to cause harm to human
health and the environment is described in more detail in
the Health and Environmental Effects Profile for UDMH (available
at the RCRA Public Docket at EPA Headquarters and at EPA
Regional Libraries).
E. Existing Regulations and Guidelines
The Resource Conservation and Recovery Act currently controls
the handling (treatmentt, storage, disposal) of the commercial
chemical product, 1,1-dimethylhydrazine (UDMH) under
40 CFR §261.33(f); and it is also listed as a hazardous constituent
under Appendix VIII of 40 CFR Part 261.
The Comprehensive Environmental Response, Compensation,
and Liability Act of 1980 (CERCLA or "Superfund"), requires
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that persons in charge of vessels or facilities from which
hazardous substances have been released in quantities that
are equal to or greater than the reportable quantities (RQs)
immediately notify the National Response Center of the release.
(See CERCLA Section 103 and 48 FR 23552, May 25, 1983.) Since
the statutory RQ for UDMH is one pound, the four waste streams
(K107, K108, K109 and K110) will also have RQs of one pound.
(Criteria are currently being developed for potential carcinogens
such as UDMH to adjust the one pound RQ to a level adequately
protective of human health and the environment.)
The Agency's Office of Pesticide Programs (OPP) is also
conducting a Special Review (RPAR) process to fully evaluate
any dietary risk to human health posed by pesticides containing
UDMH or having the possibility of conversion to UDMH. The process
was initiated by the finding that UDMH was found to be oncogenic
in laboratory animals and that UDMH has been found in raw agricultural
commodities (i.e., apples and peaches) and processed foods (i.e.,
apple sauce and apple juice). In Position Document 1 49 CFR 29136,
July 18, 1984, the Agency solicited comments on the risks and
benefits associated with all uses of these pesticides, and announced
that potential adverse effects associated with the use of these
pesticides have been identified and will be examined further to
determine their extent and whether, in light of the benefits of
the pesticides, such risks are unreasonable. (See 49 CFR 29136,
July 18, 1984.)
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T
In addition, The Occupational Safety and Health
Administration (OSHA) has set a Permissible Exposure Limit (PEL)
time-weighted average concentration for UDMH at 1 milligram per
cubic meter of air (0.5 parts per million). The National Institute
for Occupational Safety and Health (NIOSH) has recommended that
this limit be lowered to 0.15 milligrams per cubic meter.
West Germany recommends an occupational exposure limit of 0.1
parts per million.
The Department of Transportation (DOT) regulates UDMH as a
hazardous flammable materiaj..
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REFERENCES
Banerjee, S., H.C. Sikka and R. Gray. 1977. Environmental
degradation of 1,1-dimethylhydrazine. Proc. Conf. Environ.
Chem. Hydrazine Fuels, Tyndall AFB, FL. NTIS AD-AG54194.
Banerjee, S., E.J. Pack, H. Sikka and C.M. Kelly. 1981. Kinetics
of oxidation of methylhydrazines in water. Factors controlling
the formation of 1,1-dimethylnitrosamine from the corresponding
hydrazine. unpublished study. Syracuse Research Corporation,
Syracuse, NY.
Braun, B.A. and J.A. Zirrolli. 1983. Environmental fate of
hydrazine fuels in aqueous and -soil environments. Eng. Serv.
Lab., Air Force Eng. Serv. Center, Tyndall AFB, FL. Rep. No.
ESL-TR-82-45. NTIS AD-A125813. 23 p.
Bruce, W.R. and J.A. Meddle. 1979. The mutagenic activity of 61
agents as determined by the micronucleus, Salmonella and sperm
abnormality assays. Can. J. Genet. Cytol. 21:319-334.
Brusick, D. and D.W. Matheson. 1976. Mutagen and oncogen study on
1,1-dimethylhydrazine. Prepared for the Aerosp. Med. Res. Lab.,
Aerosp. Med. Div., Air Force Systems Command, Wright-Patterson AFB,
Dayton, OH. Litton Bionetics, Inc., Kensington, MD. NTIS AD-A035475
Callahan, M.A., M.W. Slimak, N.W. Gabel, et a^. 1979. Water
related environmental fate of 129 priority pollutants. Vol. II.
Dimethyl nitrosamine. EPA-440/4-79-0296.
de Flora, S. 1981. A "spiral test" applied to bacterial mutagenesis
assays. Mutat. Res. 82:213-227.
Druckrey, H., R. Preussmann, S. Ivankovic and D. Schmahl. 1967.
Organotrope carcinogene Wirkunen bei 65 verschiedenen N-Nitroso-
Verbindungen and BD ratten. ^. Krebsforsch. 69:103. (Ger.)
(Cited in IARC, 1974.)
Greenhouse, G. 1976. The evaluation of the toxic effects of
chemicals in freshwater by using frog embryos and larvae. Environ.
Pollut. 11(4):303-315.
Hanst, P.L., J.W. Spence and M. Miller. 1977. Atmospheric chemistry
of N-nitroso dimethyl amine. Environ. Sci. Technol. 11:403-405.
Kane. D.A. and K.J. Williamson. 1983. Bacterial toxicity and
metabolism of hydrazine fuels. Arch. Environ. Contain. Toxicol.
12:447-453.
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MacNaughton, M.G., J. Zirrolli, T.B. Stauffer and D.A. Stone.
1979. Environmental chemistry of hydrazine fuels. Proc.
9th Conf. Environ. Toxicol., March. Aerosp. Med. Res. Lab.,
Aerosp. Med. Div., Air Force Systems Command, Wright-Patterson
AFB, Dayton, OH. AMRL-TR79-68. p. 121-128.
Mallik, M.A.B. and K. Tesfai. 1981. Transformation of nitro-
samines in soil and in vitro by soil microorganisms. Bull.
Environ. Contain. Toxicol. 27:115-121.
Oliver, J.E., P.C. Kearney and A. Kontson. 1979. Degradation
of herbicide related nitrosamines in aerobic soils. J_. Agr ic.
Food Chem. 27:887-891.
Parodi, S., S. De Flora, M. Cavanna, et^ a±. 1981. DNA-damaging
activity in vivo and bacterial mutagenicity of sixteen hydrazine
derivatives as related quantitatively to their carcinogenicity.
Cancer Res. 41:1469-1482.
Pitts, J.H., Jr., E.G. Tuazon, W.P.L. Carter, £t al,. 1981. Atmos-
pheric chemistry of hydrazines: Gas phase kinetics and mechanitic
studies. Prepared by the Statewide Air Pollut. Res. Center, Univ.
Calif., Riverside, CA, for the Air Force Eng. Serv. Center,
Tyndall, AFB, FL. NTIS AD-A093486.
Roe, F.J.C., A.G. Grant and D.M. Millican. 1967. Carcinogenicity of
hydrazine and 1,1-dimethylhydrazine for mouse lung. Nature
216(5113):375-376.
Rogers, A.M. and K.C. Back. 1981. Comparative mutayenicity of
hydrazine and 3 methylated derivatives in L5178Y mouse lymphoma
cells. Mutat. Res. 89(4) :321-328.
Seiler, J.P. 1977. Inhibition of testicular DNA synthesis by chemical
mutagen and carcinogens. Preliminary results in the validation of
a novel short-term test. Mutat. Res. 46:305-310.
Stauffer, T.B. 1977. Hydrazine Evaporation. Proc. Conf. Environ.
Chem. Hydrazines Fuels, Tyndall AFB. NTIS AD-A054194. p. 25-38.
Tate, R.L. and M. Alexander. 1975. Stability of nitrosamines in
samples of lake water, soil and sewage. J. Natl. Cancer Inst.
54:327-330.
Toth, B. 1972. Comparative studies with hydrazine derivatives.
Carcinogenicity of 1,1-dimethylhydrazine. Unsymmetrical (1,1) DMH
in the blood vessels, lung, kidneys and liver of Swiss mice. Proc.
Am. Assoc. Cancer Res. 13:34.
Toth, B. 1973. 1,1-Dimethylhydrazine (unsymmetrical) carcinogenesis
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in mice. Light microscopic and ultrastructural studies on neoplastic
blood vessels. J. Natl. Cancer Inst. 50(1):181-194.
Toth, B. 1977. The large bowel carcinogenic effects of hydrazines
and related compounds occurring in nature and in the environment.
40:2427.
Tuazon, E.G., W.P.L. Carter, A.M. Winer and J.N. Pitts, Jr. 1981.
Reactions of hydrazines with ozone under simulated atmospheric
conditions. Environ. Sci. Technol. 15:823-828.
Wyrobek, A. J. and W. R. Brude. 1975. Chemical induction of sperm
abnormalities in mice. Proc. Natl. Acad. Sci. 72(11) :4424-4429 .
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