N-Nitroso-N-methylurea (NMU) SDS/MSDS (Safety Data Sheet)

3.1 Substances
Product name: N-Nitroso-N-methylurea (NMU)
CAS Number: 684-93-5
PubChem CID: 12699
Molecular formula: C2H5N3O2
Molecular weight: 103.08 g/mol
IUPAC name: 1-methyl-1-nitrosourea

3.2 Mixtures
Not applicable (pure substance).

4.1 Description of first aid measures
Inhalation: INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. IMMEDIATELY call a physician and be prepared to transport the victim to a hospital even if no symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater
Skin contact: SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment.
Eye contact: EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.
Ingestion: INGESTION: DO NOT INDUCE VOMITING. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. Be prepared to transport the victim to a hospital if advised by a physician. If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. IMMEDIATELY transport

4.2 Most important symptoms and effects, both acute and delayed
See Section 11 (Toxicological Information).

4.3 Indication of any immediate medical attention and special treatment needed
Treat symptomatically. Contact a poison control center or physician for severe exposure.

5.1 Extinguishing media
Suitable: Dry chemical, carbon dioxide (CO2), alcohol-resistant foam, water spray.
Unsuitable: High-pressure water jet (may spread fire).

5.2 Specific hazards arising from the substance or mixture
Fires involving this material can be controlled with a dry chemical, carbon dioxide or Halon extinguisher. A water spray may also be used. (NTP, 1992)

5.3 Advice for firefighters
Wear self-contained breathing apparatus (SCBA) and full protective clothing.
Fight fire from upwind. Cool containers with water spray until fire is extinguished.

6.1 Personal precautions, protective equipment and emergency procedures
Wear appropriate personal protective equipment (see Section 8).
Avoid breathing dust/vapor. Ensure adequate ventilation.
Evacuate personnel to safe areas. Keep people away from and upwind of spill.
WARNING: Highly toxic — only trained personnel should handle spills.

6.2 Environmental precautions
Prevent product from entering drains, waterways, or soil.
Contain spill with inert absorbent material.

6.3 Methods and materials for containment and cleaning up
Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:
IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.
SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.
FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)
PRECAUTIONS FOR "CARCINOGENS": A high-efficiency particulate arrestor (HEPA) or charcoal filters can be used to minimize amt of carcinogen in exhausted air ventilated safety cabinets, lab hoods, glove boxes or animal rooms ... Filter housing that is designed so that used filters can be transferred into plastic bag without contaminating maintenance staff is avail commercially. Filters should be placed in plastic bags immediately after removal ... The plastic bag should be sealed immediately ... The sealed bag should be labelled properly ... Waste liquids ... should be placed or collected in proper containers for disposal. The lid should be secured & the bottles properly labelled. Once filled, bottles should be placed in plastic bag, so that outer surface ... is not contaminated ... The plastic bag should also be sealed & labelled. ... Broken glassware ... should be decontaminated by solvent extraction, by chemical destruction, or in specially designed incinerators. /Chemical Carcinogens/
Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number U177, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.
A potential candidate for rotary kiln incineration at a temperature range of 820 to 1,600 °C and residence times of seconds for liquids and gases, and hours for solids. A potential candidate for fluidized bed incineration at a temperature range of 450 to 980 °C and residence times of seconds for liquids and gases, and longer for solids.
PRECAUTIONS FOR "CARCINOGENS": There is no universal method of disposal that has been proved satisfactory for all carcinogenic compounds & specific methods of chem destruction ... published have not been tested on all kinds of carcinogen-containing waste. ... summary of avail methods & recommendations ... /given/ must be treated as guide only. /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": ... Incineration may be only feasible method for disposal of contaminated laboratory waste from biological expt. However, not all incinerators are suitable for this purpose. The most efficient type ... is probably the gas-fired type, in which a first-stage combustion with a less than stoichiometric air:fuel ratio is followed by a second stage with excess air. Some ... are designed to accept ... aqueous & organic-solvent solutions, otherwise it is necessary ... to absorb soln onto suitable combustible material, such as sawdust. Alternatively, chem destruction may be used, esp when small quantities ... are to be destroyed in laboratory. /Chemical Carcinogens/
For more Disposal Methods (Complete) data for N-Nitroso-N-methylurea (8 total), please visit the HSDB record page.
PRECAUTIONS FOR "CARCINOGENS": Smoking, drinking, eating, storage of food or of food & beverage containers or utensils, & the application of cosmetics should be prohibited in any laboratory. All personnel should remove gloves, if worn, after completion of procedures in which carcinogens have been used. They should ... wash ... hands, preferably using dispensers of liq detergent, & rinse ... thoroughly. Consideration should be given to appropriate methods for cleaning the skin, depending on nature of the contaminant. No standard procedure can be recommended, but the use of organic solvents should be avoided. Safety pipettes should be used for all pipetting. /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": In animal laboratory, personnel should remove their outdoor clothes & wear protective suits (preferably disposable, one-piece & close-fitting at ankles & wrists), gloves, hair covering & overshoes. ... clothing should be changed daily but ... discarded immediately if obvious contamination occurs ... /also,/ workers should shower immediately. In chemical laboratory, gloves & gowns should always be worn ... however, gloves should not be assumed to provide full protection. Carefully fitted masks or respirators may be necessary when working with particulates or gases, & disposable plastic aprons might provide addnl protection. If gowns are of distinctive color, this is a reminder that they should not be worn outside of lab. /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": ... Operations connected with synth & purification ... should be carried out under well-ventilated hood. Analytical procedures ... should be carried out with care & vapors evolved during ... procedures should be removed. ... Expert advice should be obtained before existing fume cupboards are used ... & when new fume cupboards are installed. It is desirable that there be means for decreasing the rate of air extraction, so that carcinogenic powders can be handled without ... powder being blown around the hood. Glove boxes should be kept under negative air pressure. Air changes should be adequate, so that concn of vapors of volatile carcinogens will not occur. /Chemical Carcinogens/
PRECAUTIONS FOR "CARCINOGENS": Vertical laminar-flow biological safety cabinets may be used for containment of in vitro procedures ... provided that the exhaust air flow is sufficient to provide an inward air flow at the face opening of the cabinet, & contaminated air plenums that are under positive pressure are leak-tight. Horizontal laminar-flow hoods or safety cabinets, where filtered air is blown across the working area towards the operator, should never be used ... Each cabinet or fume cupboard to be used ... should be tested before work is begun (eg, with fume bomb) & label fixed to it, giving date of test & avg air-flow measured. This test should be repeated periodically & after any structural changes. /Chemical Carcinogens/
For more Preventive Measures (Complete) data for N-Nitroso-N-methylurea (9 total), please visit the HSDB record page.

7.1 Precautions for safe handling
SMALL SPILLS AND LEAKAGE: If you spill this chemical, you should dampen the solid spill material with 5% acetic acid, then transfer the dampened material to a suitable container. Use absorbent paper dampened with 5% acetic acid to pick up any remaining material. Your contaminated clothing and the absorbent paper should be sealed in a vapor-tight plastic bag for eventual disposal. Wash all contaminated surfaces with 5% acetic acid followed by washing with a soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned.
STORAGE PRECAUTIONS: You should protect this chemical from exposure to light. Keep the container tightly closed under an inert atmosphere, and store under refrigerated temperatures. (NTP, 1992)
PRECAUTIONS FOR "CARCINOGENS": Storage site should be as close as practical to lab in which carcinogens are to be used, so that only small quantities required for ... expt need to be carried. Carcinogens should be kept in only one section of cupboard, an explosion-proof refrigerator or freezer (depending on chemicophysical properties ...) that bears appropriate label. An inventory ... should be kept, showing quantity of carcinogen & date it was acquired ... Facilities for dispensing ... should be contiguous to storage area. /Chemical Carcinogens/
The pure compound is sensitive to humidity and light and should be refrigerated for storage.
The kinetics of N-methyl-N-nitrosourea hydrolyses are shown to be first order in N-methyl-N-nitrosourea with a steep rise in rate above pH 8. ... base-induced hydrolysis of N-methyl-N-nitrosourea is initiated by deprotonation at the carbamoyl group. The critical reactive species are shown to be the methyldiazonium ion (Me-N2+) and cyanate (NCO-). Investigations of reactions of (13CH3) N-methyl-N-nitrosourea with 2'-deoxyguanosine (dGuo) and 2'-deoxyguanosine 5'-monophosphate (dGuo-5P) showed that: a) the site of methylation of 2'-deoxyguanosine is highly pH-dependent (relatively more N-1 and O-methylation compared to N-7 occurs at higher pH); b) the principal site of methylation of 2'-deoxyguanosine 5'-monophosphate by N-methyl-N-nitrosourea is at phosphate; c) incorporation of deuterium into methyl groups occurs in D20 at higher pH. Methylation of the oligonucleotide d(GT(15N)GCAC) by N-methyl-N-nitrosourea in D20 showed partial deuteriation of the N7-methyl groups of the guanines, whilst methylation by N-methyl-N-nitrosourea in water indicated no significant preference for either guanine with respect to N7-methylation.
Keep away from heat, sparks, and open flames. Use explosion-proof equipment.

7.2 Conditions for safe storage, including any incompatibilities
PRECAUTIONS FOR "CARCINOGENS": Storage site should be as close as practical to lab in which carcinogens are to be used, so that only small quantities required for ... expt need to be carried. Carcinogens should be kept in only one section of cupboard, an explosion-proof refrigerator or freezer (depending on chemicophysical properties ...) that bears appropriate label. An inventory ... should be kept, showing quantity of carcinogen & date it was acquired ... Facilities for dispensing ... should be contiguous to storage area. /Chemical Carcinogens/
The pure compound is sensitive to humidity and light and should be refrigerated for storage.
The kinetics of N-methyl-N-nitrosourea hydrolyses are shown to be first order in N-methyl-N-nitrosourea with a steep rise in rate above pH 8. ... base-induced hydrolysis of N-methyl-N-nitrosourea is initiated by deprotonation at the carbamoyl group. The critical reactive species are shown to be the methyldiazonium ion (Me-N2+) and cyanate (NCO-). Investigations of reactions of (13CH3) N-methyl-N-nitrosourea with 2'-deoxyguanosine (dGuo) and 2'-deoxyguanosine 5'-monophosphate (dGuo-5P) showed that: a) the site of methylation of 2'-deoxyguanosine is highly pH-dependent (relatively more N-1 and O-methylation compared to N-7 occurs at higher pH); b) the principal site of methylation of 2'-deoxyguanosine 5'-monophosphate by N-methyl-N-nitrosourea is at phosphate; c) incorporation of deuterium into methyl groups occurs in D20 at higher pH. Methylation of the oligonucleotide d(GT(15N)GCAC) by N-methyl-N-nitrosourea in D20 showed partial deuteriation of the N7-methyl groups of the guanines, whilst methylation by N-methyl-N-nitrosourea in water indicated no significant preference for either guanine with respect to N7-methylation.
Store away from incompatible materials (see Section 10).
[Note: Specific storage temperature not available in public databases. Refer to supplier Certificate of Analysis (COA) for exact storage conditions.]

9.1 Information on basic physical and chemical properties
a) Appearance: N-nitroso-n-methylurea appears as pale yellow crystals or light yellow moist powder. (NTP, 1992)
b) Odor: No data available
c) Odor threshold: No data available
d) pH: No data available
e) Melting point/freezing point: 255 °F (decomposes) (NTP, 1992)
f) Initial boiling point and boiling range: No data available
g) Flash point: No data available
h) Evaporation rate: No data available
i) Flammability (solid, gas): No data available
j) Upper/lower flammability or explosive limits: No data available
k) Vapor pressure: Non-volatile (NTP, 1992)
l) Vapor density: No data available
m) Relative density: less than 1.0 (NTP, 1992)
n) Water solubility: less than 1 mg/mL at 64 °F (NTP, 1992)
o) Partition coefficient: n-octanol/water: Log P: 0
p) Auto-ignition temperature: No data available
q) Decomposition temperature: No data available
r) Viscosity: No data available
s) Explosive properties: No data available
t) Oxidizing properties: No data available

9.2 Other information
Topological Polar Surface Area (TPSA): 75.8 Ų
Complexity: 90

11.1 Information on toxicological effects
Acute toxicity:
No acute toxicity data available.
Skin corrosion/irritation:
No data available.
Serious eye damage/eye irritation:
No data available.
Respiratory or skin sensitization:
May cause an allergic skin reaction (H317).
Germ cell mutagenicity:
May cause genetic defects (H340).
Carcinogenicity:
May cause cancer (H350).
Reproductive toxicity:
May damage fertility or the unborn child (H360).
Specific target organ toxicity (single exposure):
No data available.
Specific target organ toxicity (repeated exposure):
No data available.
Aspiration hazard:
No data available.

11.2 Additional information
Carcinogen classification:
N-Methyl-N-nitrosourea
Group 2A: Probably carcinogenic to humans
Volume 17: (1978) Some N-Nitroso Compounds
Volume Sup 7: Overall Evaluations of Carcinogenicity: An Updating of IARC Monographs Volumes 1 to 42, 1987; 440 pages; ISBN 92-832-1411-0 (out of print)
1987
1987
NB Overall evaluation upgraded to Group 2A with supporting evidence from other relevant data
Data source: Hazardous Substances Data Bank (HSDB) via PubChem.

12.1 Toxicity
LC50; Species: Oryzias latipes (Japanese medaka) embryo, 66 hr post-fertilization; Conditions: freshwater, static; Concentration: 206.1612 mg/L for 2 hr (95% confidence interval: 164.92896-257.7015 mg/L)
EC50; Species: Oryzias latipes (Japanese medaka) embryo, 66 hr post-fertilization; Conditions: freshwater, static; Concentration: 154.6209 mg/L for 2 hr (95% confidence interval: 134.00478-185.54508 mg/L); Effect: abnormal growth
1.00e-03
1.90e-02
3e-05
3.60e-04
2.10e-04
1.00e+03
4.6e-08
1.20e+02
3.40e-02
Volatile
Mutagen
1
0.1
1.00e-01
1.90e+00
3.00e-03
3.60e-02
2.10e-02
1.00e+03
1.20e+02
3.40e-02
Volatile
Mutagen
1
0.1
N-Nitroso-N-methylurea's limited production and use in laboratory synthesis for research purposes may result in its release to the environment through laboratory waste streams. No evidence was found that N-nitroso-N-methylurea is produced or used commercially. If released to air, an estimated vapor pressure of 3.0X10-2 mm Hg at 25 °C indicates N-nitroso-N-methylurea will exist solely as a vapor in the atmosphere. Vapor-phase N-nitroso-N-methylurea will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 10 days. N-Nitroso compounds, such as N-nitroso-N-methylurea, absorb UV light at wavelengths of approximately 330 nm and, therefore, N-nitroso-N-methylurea may be susceptible to direct photolysis by sunlight since sunlight consists of wavelengths above 290 nm. If r

12.2 Persistence and degradability
No data available.

12.3 Bioaccumulative potential
No data available.

12.4 Mobility in soil
No data available.

12.5 Results of PBT and vPvB assessment
PBT/vPvB assessment not available.

12.6 Other adverse effects
No other adverse ecological effects identified.

13.1 Waste treatment methods
Waste Treatment Methods: Waste material must be disposed of in accordance with national and local regulations. Leave chemicals in original containers and do not mix with other waste. Handle uncleaned containers in the same manner as the product itself.

14.1 UN number
Not regulated as dangerous goods (research quantities typically exempt).

14.2 UN proper shipping name
Not subject to transport regulations (small quantities for research use).

14.3 Transport hazard class(es)
Not classified as dangerous goods for transport (research quantities).
DOT label: Poison

14.4 Packing group
Not applicable (not regulated as dangerous goods in typical research quantities).

14.5 Environmental hazards
Marine pollutant: No (not classified as environmentally hazardous per GHS).

14.6 Special precautions for user
Transport in original packaging. Ensure containers are tightly sealed.
For bulk or commercial quantities, consult applicable transport regulations (DOT, IATA, IMDG).

14.7 Transport in bulk according to Annex II of MARPOL 73/78 and the IBC Code
Not applicable.

15.1 Safety, health and environmental regulations/legislation specific for the substance or mixture
US EPA / TSCA: Subject to EPA TSCA regulations
EU ECHA / REACH: Not available in public databases.

SARA 302 Components:
No chemicals in this material are subject to the reporting requirements of SARA Title III, Section 302.
SARA 313 Components:
This material does not contain any chemical components with known CAS numbers that exceed the threshold (De Minimis) reporting levels established by SARA Title III, Section 313.
SARA 311/312 Hazards:
Acute (short-term) health hazard
Chronic (long-term) health hazard
Fire hazard

Massachusetts Right To Know Components:
This material contains components subject to the Massachusetts Right to Know Act. See Section 2 for hazard classification.
Pennsylvania Right To Know Components:
This material contains components subject to the Pennsylvania Right to Know Act. See Section 2 for hazard classification.
New Jersey Right To Know Components:
This material contains components subject to the New Jersey Right to Know Act. See Section 2 for hazard classification.

California Prop. 65 Components:
This product does not contain any chemicals known to the State of California to cause cancer, birth defects, or any other reproductive harm.

Other regulatory listings:
- California Safe Cosmetics Program (CSCP) Reportable Ingredient: Hazard Traits - Carcinogenicity; Dermatotoxicity Authoritative List - CA TACs; IARC Carcinogens - 2A; NTP RoC - reasonable; Prop 65 Report - regardless of intended function of ingredient in the produc
- New Jersey Worker and Community Right to Know Act: The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.)
- Atmospheric Standards: Listed as a hazardous air pollutant (HAP) generally known or suspected to cause serious health problems. The Clean Air Act, as amended in 1990, directs EPA to set standards requiring major sources to sharply reduce routine emissions of toxic pollutants. EPA is required to establish and phase in spec
- CERCLA Reportable Quantities: Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 1 lb or 0.454 kg. The toll free number of the NRC is (800
- RCRA Requirements: U177; As stipulated in 40 CFR 261.33, when N-nitroso-N-methylurea, as a commercial chemical product or manufacturing chemical intermediate or an off-specification commercial chemical product or a manufacturing chemical intermediate, becomes a waste, it must be managed according to Federal and/or Sta

15.2 Chemical safety assessment
A chemical safety assessment has not been carried out for this substance.
For research-use-only compounds, no CSA is required under REACH Annex I.

Revision Date: 2026/09/08
Further Information: The information provided is believed to be correct but is not exhaustive and should be used only as a guideline based on current knowledge. It does not represent a guarantee of the properties of the product. Selleck Chemicals Corporation and its Affiliates shall not be held liable for any damage resulting from handling or contact with the product.