Mequinol SDS/MSDS (Safety Data Sheet)

3.1 Substances
Product name: Mequinol
CAS Number: 150-76-5
PubChem CID: 9015
Molecular formula: C7H8O2
Molecular weight: 124.14 g/mol
IUPAC name: 4-methoxyphenol

3.2 Mixtures
Not applicable (pure substance).

4.1 Description of first aid measures
Inhalation: Fresh air, rest.
Skin contact: Remove contaminated clothes. Rinse and then wash skin with water and soap.
Eye contact: First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.
Ingestion: Rinse mouth. Give one or two glasses of water to drink. Refer for medical attention .

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: Water spray, dry chemical, carbon dioxide (CO2), alcohol-resistant foam.
Unsuitable: None known.

5.2 Specific hazards arising from the substance or mixture
Excerpt from ERG Guide 171 [Substances (Low to Moderate Hazard)]:
CAUTION: Fire involving Safety devices (UN3268) and Fire suppressant dispersing devices (UN3559) may have a delayed activation and a risk of hazardous projectiles. Extinguish the fire at a safe distance.
SMALL FIRE: Dry chemical, CO2, water spray or regular foam.
LARGE FIRE: Water spray, fog or regular foam. Do not scatter spilled material with high-pressure water streams. If it can be done safely, move undamaged containers away from the area around the fire. Dike runoff from fire control for later disposal.
FIRE INVOLVING TANKS: Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. (ERG, 2024)
Use water spray, powder, alcohol-resistant foam, carbon dioxide.
Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Advice for fire fighters: Wear self contained breathing apparatus for fire fighting if necessary.
Water or foam may cause frothing.

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.
Flash point: 269.6 °F (NTP, 1992)

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.

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 171 [Substances (Low to Moderate Hazard)]:
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)
Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Sweep spilled substance into covered sealable containers. Carefully collect remainder. Then store and dispose of according to local regulations.
Personal precautions, protective equipment and emergency procedures: Use personal protective equipment. Avoid dust formation. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Avoid breathing dust.
Enviornomental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided.
Methods and materials for containment and cleaning up: Pick up and arrange disposal without creating dust. Sweep up and shovel. keep in suitable, closed containers for disposal.
SRP: Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.
SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.
The worker should immediately wash the skin when it becomes contaminated.
Work clothing that becomes wet or significantly contaminated should be removed and replaced.
Precautions for safe handling: Avoid contact with skin and eyes. Avoid formation of dust and aerosols. Provide appropriate exhaust ventilation at places where dust is formed.
For more Preventive Measures (Complete) data for 4-METHOXYPHENOL (6 total), please visit the HSDB record page.

7.1 Precautions for safe handling
SMALL SPILLS AND LEAKAGE: Should a spill occur while you are handling this chemical, you should dampen the solid spill material with alcohol, then transfer the dampened material to a suitable container. Use absorbent paper dampened with alcohol to pick up any remaining material. Seal the absorbent paper, and any of your clothes, which may be contaminated, in a vapor-tight plastic bag for eventual disposal. Solvent wash all contaminated surfaces with alcohol followed by washing with a strong soap and water solution. Do not reenter the contaminate area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned.
STORAGE PRECAUTIONS: You should store this material in a refrigerator. (NTP, 1992)
Separated from strong oxidants, strong bases, acid anhydrides and acid chlorides.
Conditions for safe storage, including any incompatibilities: Keep container tightly closed in a dry and well-ventilated place.
... Commercially available mequinol and tretinoin topical solution should be protected from light and stored at room temperature, preferably in the manufacturer's carton. /Solage/
Store at 25 °C (77 °F): excursions permitted to 15-30 °C (59-86 °F).

7.2 Conditions for safe storage, including any incompatibilities
Separated from strong oxidants, strong bases, acid anhydrides and acid chlorides.
Conditions for safe storage, including any incompatibilities: Keep container tightly closed in a dry and well-ventilated place.
... Commercially available mequinol and tretinoin topical solution should be protected from light and stored at room temperature, preferably in the manufacturer's carton. /Solage/
Store at 25 °C (77 °F): excursions permitted to 15-30 °C (59-86 °F).
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: Hydroquinone monomethyl ether appears as pink crystals or white waxy solid. (NTP, 1992)
b) Odor: Odor of caramel and phenol
c) Odor threshold: No data available
d) pH: No data available
e) Melting point/freezing point: 126.5 °F (NTP, 1992)
f) Initial boiling point and boiling range: 475 °F at 760 mmHg (NTP, 1992)
g) Flash point: 269.6 °F (NTP, 1992)
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: less than 0.01 mmHg (NIOSH, 2024)
l) Vapor density: No data available
m) Relative density: 1.55 at 68 °F (NTP, 1992) - Denser than water; will sink
n) Water solubility: Soluble (NTP, 1992)
o) Partition coefficient: n-octanol/water: Log P (n-octanol/water): 1.3
p) Auto-ignition temperature: 790 °F (NTP, 1992)
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): 29.5 Ų
Complexity: 75

11.1 Information on toxicological effects
Acute toxicity:
No acute toxicity data available.
Skin corrosion/irritation:
Causes skin irritation (H315).
Serious eye damage/eye irritation:
Causes serious eye irritation (H319).
Respiratory or skin sensitization:
May cause an allergic skin reaction (H317).
Germ cell mutagenicity:
No data available.
Carcinogenicity:
Suspected of causing cancer (H351).
Reproductive toxicity:
Suspected of damaging fertility or the unborn child (H361).
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
Exposure routes:
The substance can be absorbed into the body by ingestion.
inhalation, skin absorption, ingestion, skin and/or eye contact
Signs and symptoms of exposure:
Redness. Burning sensation. Pain.
Redness. Pain.
irritation eyes, skin, nose, throat, upper respiratory system; eye, skin burns; central nervous system depression
Data source: Hazardous Substances Data Bank (HSDB) via PubChem.

12.1 Toxicity
EC50; Species: Daphnia magna (Water flea); Conditions: freshwater, static, 19-20 °C, pH 7.4-7.8, dissolved oxygen 7.7-8.6 at test start and 5.5-6.1 at test end; Concentration: 2.2 mg/L for 48 hr; Effect: immobilization
LC50; Species: Daphnia magna (Water flea) age < or =24 hr; Conditions: freshwater, static, 20-22 °C, pH 7.6-7.7; Concentration: 19000 ug/L for 24 hr /formulated product/
LC50; Species: Pimephales promelas (Fathead minnow); Conditions: freshwater, static, 19-20 °C, pH 7.4-7.8; Concentration: 55 mg/L for 96 hr
LC50; Species: Pimephales promelas (Fathead minnow) juvenile, age 26-34 days; Conditions: freshwater, flow through, 25 °C, pH 7.8, hardness 45 mg/L CaCO3, alkalinity 42 mg/L CaCO3; Concentration: 84300 ug/L for 96 hr /> or = 95% purity/
For more Ecotoxicity Values (Complete) data for 4-METHOXYPHENOL (9 total), please visit the HSDB record page.
4-Methoxyphenol's production and use in the manufacture of antioxidants, pharmaceuticals, plasticizers, dyestuffs, as a stabilizer for chlorinated hydrocarbons and ethyl cellulose, and as an inhibitor for acrylic monomers and acrylonitriles may result in its release to the environment through various waste streams. 4-Methoxyphenol is reported to occur in licorice root and sesame seed. If released to air, a vapor pressure of 6.75X10-3 mm Hg at 20 °C indicates 4-methoxyphenol will exist solely as a vapor in the atmosphere. Vapor-phase 4-methoxyphenol will be degraded in the atmosphere by reaction with photochemically-p

12.2 Persistence and degradability
No data available.

12.3 Bioaccumulative potential
Log P (n-octanol/water): 1.3
Low potential for bioaccumulation (Log P < 3).

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
This substance is classified as hazardous to the aquatic environment.

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: Class 9

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

14.5 Environmental hazards
Marine pollutant: Yes (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: Registered (REACH Active)

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
Environmental 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:
- The Australian Inventory of Industrial Chemicals: Chemical: Phenol, 4-methoxy-
- EFSA Legal Basis: Commission Regulation (EC) No 1565/2000 (Repealed by Com. Implementing Reg. (EU) No 872/2012)
- TSCA Requirements: Section 8(a) of TSCA requires manufacturers of this chemical substance to report preliminary assessment information concerned with production, exposure, and use to EPA as cited in the preamble in 51 FR 41329. Effective date: 3/11/94; Reporting date: 5/10/94.
Pursuant to section 8(d) of TSCA, EPA pro

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: 2026/09/09
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.