Dichloromethane Safety, Hazards & Handling:
SDS Guide for Industrial Users
GHS classification · OEL by jurisdiction · PPE · Storage · Emergency response · SDS checklist
🔗 View DCM Product Page⚠️ Important: This article is an informational reference only and does not replace a site-specific risk assessment or a compliant Safety Data Sheet (SDS) from your supplier. Always obtain and review the current SDS before handling DCM. If you require an SDS for Sinolook Chemical's DCM, contact us directly.
📋 Table of Contents
- GHS Hazard Classification & Pictograms
- Health Hazards: Acute & Chronic Effects
- Occupational Exposure Limits by Jurisdiction
- Personal Protective Equipment (PPE)
- Storage Requirements & Incompatibilities
- Emergency Response: Fire, Spill & First Aid
- Transport Classification (UN 1593)
- SDS Compliance Checklist - What to Verify
- Frequently Asked Questions
⚠️ 1. GHS Hazard Classification & Pictograms
Under the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), dichloromethane carries multiple hazard classifications. The most significant from a workplace management perspective are its carcinogen classification (IARC Group 1, GHS Carc. 1A) and its specific target organ toxicity from repeated inhalation exposure.
H332: Harmful if inhaled
IDLH: 2,300 ppm (NIOSH)
H350: May cause cancer
IARC Group 1 (2023 reclassification)
H372: Causes damage to organs (CNS, liver) through prolonged or repeated exposure
Route: Inhalation
H336: May cause drowsiness or dizziness
CNS narcotic effect at elevated concentrations
| Code | Type | Statement |
|---|---|---|
| H332 | Hazard - Acute tox. | Harmful if inhaled |
| H350 | Hazard - Carcinogen | May cause cancer (inhalation) |
| H372 | Hazard - STOT RE | Causes damage to organs through prolonged or repeated exposure |
| H336 | Hazard - STOT SE | May cause drowsiness or dizziness |
| P260 | Precaution - Prevention | Do not breathe vapours |
| P271 | Precaution - Prevention | Use only outdoors or in a well-ventilated area |
| P280 | Precaution - Prevention | Wear protective gloves, eye/face protection, and respiratory protection |
| P304+P340 | Precaution - Response | IF INHALED: Remove person to fresh air; keep comfortable for breathing |
| P308+P313 | Precaution - Response | If exposed or concerned: Get medical advice/attention |
| P405+P501 | Precaution - Storage/Disposal | Store locked up; dispose of contents in accordance with local regulations |
🫁 2. Health Hazards: Acute & Chronic Effects
DCM's health hazard profile is dominated by two distinct mechanisms: the acute narcotic effect of high inhalation exposure, and the chronic carcinogenic risk from long-term lower-level exposure. Understanding both is essential for appropriate risk management.
⚡ Acute Exposure Effects (Short-term, High Concentration)
| Concentration (ppm) | Duration | Observed Effects |
|---|---|---|
| 100–200 | 8 hours | Near OEL level; possible mild headache; generally well tolerated with good ventilation |
| 300–500 | 1–4 hours | Headache, light-headedness, impaired psychomotor performance, nausea |
| 500–1,000 | Minutes–hours | Marked dizziness, visual disturbances, reduced coordination, CO accumulation in blood |
| 1,000–2,000 | Minutes | Severe CNS depression, unconsciousness possible; significant carboxyhaemoglobin (COHb) elevation |
| >2,300 (IDLH) | Minutes | Life-threatening; cardiac arrhythmia risk; rapid loss of consciousness; fatal at higher levels |
❤️ Cardiac Sensitisation Risk - Critical Warning for Cardiac Patients
DCM is metabolised in the body to carbon monoxide (CO), elevating carboxyhaemoglobin (COHb) levels in blood. For healthy workers at OEL-compliant exposure levels, this CO load is generally manageable. However, for workers with ischaemic heart disease, angina, or other cardiovascular conditions, even moderate DCM exposure can precipitate cardiac events. Workers with known cardiovascular disease should not work with DCM without specialist occupational health assessment. This is a mandatory consideration in OSHA's DCM standard (29 CFR 1910.1052).
📅 Chronic Exposure Effects (Long-term, Repeated Exposure)
In 2023, IARC reclassified DCM from Group 2A (probable) to Group 1 (known human carcinogen), based on sufficient evidence for non-Hodgkin lymphoma and limited evidence for other cancers. This is the highest IARC category - the same as benzene and formaldehyde.
Chronic low-level inhalation is associated with neurobehavioural effects: impaired memory, reduced reaction time, and psychomotor deficits. These effects may be partially reversible upon cessation of exposure if detected early.
Liver enzyme elevation has been observed in workers with chronic occupational exposure. DCM is metabolised via two pathways - oxidative (CYP2E1, producing CO) and conjugative (GST, producing formaldehyde-glutathione adducts) - both of which can contribute to hepatotoxicity at high chronic doses.
📊 3. Occupational Exposure Limits by Jurisdiction
Occupational Exposure Limits (OELs) for DCM vary significantly between jurisdictions - from the strict 25 ppm TWA in the United States to the more permissive 200 mg/m³ (~57 ppm) TWA in China. The table below is critical reference material for any employer operating in multiple markets or importing DCM for use across different countries.
| Country / Authority | TWA (ppm) | TWA (mg/m³) | STEL (ppm) | Regulatory Basis | Skin Notation |
|---|---|---|---|---|---|
| 🇺🇸 USA - OSHA | 25 ppm | 87 mg/m³ | 125 ppm | 29 CFR 1910.1052 | Yes |
| 🇺🇸 USA - NIOSH REL | Ca (carcinogen) | - | - | NIOSH Pocket Guide | Yes |
| 🇺🇸 USA - ACGIH TLV | 50 ppm | 174 mg/m³ | - | ACGIH TLV-TWA | Yes |
| 🇪🇺 EU | 100 ppm | 353 mg/m³ | 300 ppm | Directive 2017/164/EU | - |
| 🇬🇧 UK | 100 ppm | 353 mg/m³ | 300 ppm | EH40 WEL | - |
| 🇩🇪 Germany | 100 ppm | 353 mg/m³ | - | TRGS 900 (MAK value) | Yes (H) |
| 🇨🇳 China | ~57 ppm | 200 mg/m³ | - | GBZ 2.1-2019 | - |
| 🇯🇵 Japan | 50 ppm | 174 mg/m³ | - | MHLW / JSOH | - |
| 🇦🇺 Australia | 50 ppm | 174 mg/m³ | 300 ppm | Safe Work Australia WES | - |
💡 OEL compliance in practice: Given DCM's IARC Group 1 carcinogen status, the precautionary principle suggests targeting exposure levels as low as reasonably achievable (ALARA) rather than simply meeting the legal OEL. NIOSH treats DCM as a carcinogen with no established safe level and recommends the lowest feasible concentration. Even in jurisdictions with higher OELs (China: 200 mg/m³, EU: 353 mg/m³), implementing engineering controls to keep exposure well below the OEL is best practice.
🧤 4. Personal Protective Equipment (PPE)
PPE for DCM must address three primary exposure routes: inhalation (dominant route of concern), skin contact (dermal absorption is significant), and eye/mucous membrane contact. The hierarchy of controls - elimination, substitution, engineering controls, administrative controls, PPE - should always be applied with PPE as the last line of defence, not the first.
Half-face respirator with organic vapour (OV) cartridge
Above OEL or poor ventilation:
Supplied-air respirator (SAR) or self-contained breathing apparatus (SCBA)
US OSHA requirement:
Supplied-air respirator mandatory for exposures >100 ppm; airline respirator for depainting operations
⚠️ Standard OV cartridges provide only limited protection - their service life is short at DCM's high vapor pressure. Do not reuse cartridges beyond the calculated end-of-service-life.
Acceptable: Neoprene or nitrile (thicker gauges only)
Not suitable: Natural latex, PVC, or standard nitrile (thin) - DCM permeates rapidly
Breakthrough times (approx.):
Butyl rubber 0.5mm: >480 min ✅
Nitrile 0.38mm: <30 min ❌
Natural latex 0.5mm: <10 min ❌
Always verify breakthrough times with the specific glove manufacturer's data - DCM is notoriously aggressive toward many glove materials.
For splash risk: Full-face shield in addition to goggles
Not adequate: Standard safety glasses - no side protection against vapour or splash
DCM causes immediate pain and tearing on eye contact. Flush with water for 15 minutes if splash occurs. Seek medical attention if irritation persists.
High splash risk / large volumes: Full chemical protective suit (Type 3 or Type 4 per EN 14605)
Material note: Ordinary cotton and polyester work clothing provide no meaningful protection against DCM vapour or liquid contact. Ensure no liquid DCM contacts skin - dermal absorption is significant and adds to systemic CO load.
🏭 5. Storage Requirements & Incompatibilities
While DCM is not classified as a flammable liquid, its storage still requires careful attention to temperature, container integrity, ventilation, and incompatible materials. DCM's high vapor pressure (47.4 kPa at 20 °C) means significant headspace pressure builds in sealed containers, and vapour levels in poorly ventilated storage areas can quickly reach concentrations of concern.
- Store in cool, well-ventilated area (ideally <25 °C)
- Keep containers tightly closed when not in use
- Store in original UN-certified steel drums
- Protect from direct sunlight and heat sources
- Area must have local exhaust ventilation or continuous air monitoring
- Ground storage area to prevent static build-up (even though DCM itself is not flammable, antistatic measures are good practice)
- Inventory management: FIFO (first in, first out) - DCM is stable but long storage allows slow HCl build-up
- Post GHS hazard labels and emergency contact information visibly
- Strong alkalis / bases (NaOH, KOH, Ca(OH)₂) - react to form dichlorocarbene, CO, and other toxic products
- Strong oxidising agents (HNO₃, peroxides, permanganates) - risk of violent reaction
- Finely divided metals (aluminium powder, magnesium) - potential exothermic reaction
- Chemically active metals (sodium, potassium, lithium) - violent reaction with evolution of HCl
- Plastics susceptible to DCM - PVC, PC, ABS, PMMA containers are inappropriate for storage
Container materials for DCM storage: Steel, HDPE (high-density polyethylene), PTFE, and glass are all compatible. Do not use PVC, ABS, or standard nylon containers.
💡 Shelf life and stability: DCM is inherently stable and does not form peroxides (unlike diethyl ether or THF). However, slow hydrolysis in the presence of moisture produces HCl and formaldehyde - which is why commercial DCM contains 10–50 ppm of an acid-scavenging stabiliser (typically an epoxide). Recommended shelf life in sealed original drums is 2 years. Always verify acidity (HCl) on the COA and request re-testing if drums have been stored >2 years before use.
🚨 6. Emergency Response: Fire, Spill & First Aid
In a fire involving other materials: DCM vapours may contribute to fire if present at >13% concentration
Combustion products: HCl (hydrochloric acid vapour), phosgene (COCl₂), CO - all highly toxic
Extinguishing agents: CO₂, dry chemical powder, or foam. Water mist acceptable; avoid directing water jet into liquid DCM
PPE for firefighters: Full SCBA and chemical-protective clothing - do not enter fire area without full protection
1. Evacuate personnel not wearing appropriate PPE
2. Ventilate area immediately
3. Absorb with inert material (vermiculite, dry sand, earth) - avoid sawdust (flammable)
4. Collect contaminated absorbent in labelled, sealed container
5. Dispose as hazardous chemical waste per local regulations
Large spill (>5 L):
Notify emergency services; isolate the area; prevent entry into drains, watercourses, or confined spaces (DCM vapour is heavier than air and accumulates in low-lying areas)
⚠️ DCM is denser than air - vapour settles to floor level; particular hazard in basements and trenches
Remove to fresh air immediately. Keep person comfortable for breathing. If not breathing, apply CPR. Seek medical attention immediately - inform physician of DCM exposure and carboxyhaemoglobin risk
Skin contact:
Remove contaminated clothing. Wash skin with soap and water for at least 15 minutes. Seek medical attention if irritation develops
Eye contact:
Flush with clean water for at least 15 minutes, holding eyelids open. Seek immediate medical attention
Ingestion:
Do NOT induce vomiting. Rinse mouth with water. Seek immediate medical attention - inform physician of ingested substance
🚢 7. Transport Classification (UN 1593)
DCM is classified as a dangerous good for all modes of international transport. The classification is consistent across sea, air, road, and rail regulations, though specific requirements for documentation and packaging vary by mode.
| Parameter | Classification | Notes |
|---|---|---|
| UN Number | UN 1593 | Dichloromethane (specific UN number) |
| Proper Shipping Name | Dichloromethane | Also accepted: Methylene chloride |
| Hazard Class | Class 6.1 (Toxic substances) | Primary hazard: Toxic |
| Packing Group | III (Low danger) | Within Class 6.1 - lowest packing group |
| Labels Required | Class 6.1 toxic (skull & crossbones) | On each package and container |
| Sea (IMDG) | IMDG Code 6.1; Stowage Cat. A | DGD required; no stowage restriction under Cat. A |
| Air (IATA) | Passenger: 60 L per package; Cargo: 220 L | Packing Instruction 602; rarely practical for bulk - sea freight strongly preferred |
| Road (ADR / 49 CFR) | ADR Class 6.1; 49 CFR §172.101 | Standard PG III requirements; no tunnel restriction |
| Emergency Response Guide | ERG Guide 160 | North American emergency response reference |
📄 8. SDS Compliance Checklist - What to Verify
When receiving a Safety Data Sheet for DCM from a supplier, the following checklist identifies the minimum content required under GHS/REACH Section 31 (16-section SDS format). Use this as a quick-review tool before accepting a new supplier or a revised SDS revision.
| Section | SDS Section Title | Key Items to Verify for DCM | Priority |
|---|---|---|---|
| 1 | Identification | CAS 75-09-2 confirmed; supplier contact including emergency telephone number | ⭐⭐⭐ |
| 2 | Hazard Identification | GHS categories present: Acute Tox. 4 (inhal.); Carc. 1A; STOT RE 1; STOT SE 3. H350 present (carcinogen). Signal word: DANGER | ⭐⭐⭐ |
| 3 | Composition | Purity ≥99% (or stated grade); stabiliser type identified (epoxide stabiliser common) | ⭐⭐ |
| 7 | Handling & Storage | Ventilation requirements stated; incompatibles listed; container material compatibility noted | ⭐⭐⭐ |
| 8 | Exposure Controls / PPE | OEL for at least one jurisdiction stated; glove material specified (butyl rubber); respiratory protection type stated; DNEL/PNEC present (for EU REACH) | ⭐⭐⭐ |
| 9 | Physical & Chemical Properties | Boiling point 39.6 °C; density 1.325 g/cm³; flash point "None"; vapour pressure 47.4 kPa; explosive limits 13–23% | ⭐⭐ |
| 10 | Stability & Reactivity | Phosgene formation on decomposition mentioned; incompatibles listed (strong alkalis, oxidisers, reactive metals) | ⭐⭐⭐ |
| 11 | Toxicological Information | IARC Group 1 carcinogen status stated; CO metabolite and cardiac sensitisation mentioned; IDLH 2,300 ppm; LC₅₀ data present | ⭐⭐⭐ |
| 14 | Transport Information | UN 1593 confirmed; Class 6.1; PG III; proper shipping name "Dichloromethane" or "Methylene chloride" | ⭐⭐⭐ |
| 15 | Regulatory Information | TSCA listing confirmed (US); REACH registration number present (EU); SVHC candidate status noted; applicable national restrictions referenced | ⭐⭐ |
❓ 9. Frequently Asked Questions
Q1: Is dichloromethane a confirmed human carcinogen?
Yes - as of 2023. The International Agency for Research on Cancer (IARC) upgraded DCM from Group 2A (probable human carcinogen) to Group 1 (known human carcinogen) in its Monograph 132, based on sufficient evidence for non-Hodgkin lymphoma and limited evidence for several other cancer types. This reclassification placed DCM in the same category as benzene, formaldehyde, and asbestos. While the cancer risk at low occupational exposures is quantitatively different from these benchmark carcinogens, the classification reinforces the requirement to minimize exposure as far as reasonably practicable.
Q2: Why is DCM particularly dangerous for people with heart conditions?
DCM is metabolised in the body to carbon monoxide (CO) via the CYP2E1 enzyme pathway. Even at permissible workplace concentrations, this metabolism can elevate carboxyhaemoglobin (COHb) to 3–5% - levels that reduce the blood's oxygen-carrying capacity and increase cardiac workload. For individuals with ischaemic heart disease, angina pectoris, or other conditions where cardiac oxygen supply is already marginal, this additional CO burden can trigger angina attacks, arrhythmias, or myocardial infarction. Several fatal occupational DCM exposures have involved individuals with underlying but previously undiagnosed cardiac disease.
Q3: Can I use a standard organic vapour cartridge respirator for DCM?
For very low exposures (well below OEL in well-ventilated spaces), an OV half-face respirator provides some protection. However, DCM's high vapour pressure means cartridges are depleted much faster than for higher-boiling solvents - estimated service life for DCM OV cartridges may be as short as 30–60 minutes under high-concentration conditions, far shorter than the standard 8-hour shift assumption. The US OSHA DCM standard requires supplied-air respirators for exposures above 100 ppm or for operations such as aircraft depainting. For routine lower-level work, if using OV cartridges, calculate the end-of-service life using OSHA's or the cartridge manufacturer's models and change cartridges well before this limit.
Q4: Does DCM form peroxides during storage like ether solvents?
No - DCM does not form explosive peroxides during storage. This is one safety advantage it has over ether solvents like diethyl ether or THF, which require periodic peroxide testing and disposal. DCM's main storage decomposition pathway is slow hydrolysis in the presence of water to form HCl and formaldehyde - which is why commercial DCM contains acid-scavenging stabilisers and why acidity is a key COA parameter to monitor on stored material.
Q5: What should I do if a worker is overexposed to DCM vapour?
Immediately remove the worker to fresh air. Keep them at rest in a comfortable breathing position. Call emergency medical services if the worker is unconscious, having difficulty breathing, or complaining of chest pain - the cardiac risk from CO elevation is real and requires medical evaluation. Inform the attending physician that the substance is DCM and that carboxyhaemoglobin (COHb) may be elevated - oxygen therapy is the primary treatment. Do not leave the worker unattended. Review ventilation controls and monitoring systems to prevent recurrence before resuming operations.
Q6: Does the SDS from a Chinese DCM supplier meet EU/US requirements?
Chinese suppliers typically issue SDS documents compliant with Chinese GB/T 17519 standard (which aligns with GHS), but these may not automatically meet all requirements of EU REACH Annex II (16-section REACH-compliant SDS) or OSHA Hazard Communication Standard (29 CFR 1910.1200). Key gaps to check: (1) EU REACH registration number may be absent for non-EU registered substances; (2) DNEL/PNEC values required for EU compliance; (3) OEL values should reflect your jurisdiction, not only Chinese standards. Request an SDS explicitly prepared for your destination market, or verify that the Chinese SDS contains all 16 required sections with jurisdiction-appropriate content before use.
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