Toxicology – Carbon Disulfide

Core concept

Carbon disulfide (CS₂) is a highly volatile, extremely flammable industrial solvent that can cause acute CNS/respiratory toxicity and chronic neurovascular disease.

The characteristic syndromes are:

Acute high-dose exposure → headache/dizziness → intoxication → agitation or CNS depression → seizures/coma ± respiratory failure

and:

Chronic occupational exposure → distal sensorimotor polyneuropathy + neurobehavioral/CNS effects + cardiovascular disease ± retinal microvascular injury

The most important intervention is:

Immediate removal from exposure + supportive airway/ventilatory care

There is no proven specific antidote.

Physical Properties

Carbon disulfide is:

• Chemical formula: CS₂
• Colorless to faint-yellow liquid
• Highly volatile
• Poorly water soluble
• Lipophilic
• Extremely flammable

Pure CS₂ may have a sweet, ether-like odor, while technical-grade material can smell unpleasant because of sulfur contaminants.

Important physical properties include:

• Boiling point: approximately 46°C / 116°F
• Flash point: approximately −30°C / −22°F
• Lower explosive limit: approximately 1.3%
• Upper explosive limit: approximately 50%

Major safety point

Fire and explosion risk are major hazards.

Carbon disulfide vapors can ignite extremely easily, potentially even from relatively low-energy ignition sources.

Forms and Uses

Current and historical industrial uses include:

• Viscose rayon manufacture
• Cellophane production
• Rubber processing
• Dyes
• Pesticide-related manufacture
• Industrial solvents
• Chemical synthesis
• Cleaning/degreasing applications

Historically, large occupational cohorts were exposed in the viscose rayon industry, which forms much of the evidence base for chronic carbon disulfide toxicity.

Routes of Exposure

Important routes are:

• Inhalation
• Dermal absorption
• Ingestion
• Eye contact

NIOSH specifically assigns carbon disulfide a skin notation, meaning clinically meaningful systemic absorption can occur through skin exposure.

In occupational settings, inhalation is usually the most important route.

Toxic Dose / Concentration

There is no single reliable toxic concentration because toxicity depends strongly on:

Air concentration × duration of exposure

as well as:

• Ventilation
• Workload
• Dermal absorption
• Individual susceptibility
• Coexposures

Acute inhalation

Historical human data suggest:

• Several hundred ppm can produce obvious acute neurologic symptoms
• Around 420–510 ppm has produced symptoms within 30 minutes
• Approximately 1,100 ppm can cause severe symptoms/unconsciousness
• Around 4,800–5,000 ppm for approximately 30–60 minutes has been associated with coma and death

Thus, the older statement:

“4,800 ppm for 1 hour is fatal”

should be understood as a historical observation, not a fixed threshold.

IDLH

Current NIOSH:

IDLH = 500 ppm

Pathophysiology

Carbon disulfide has several toxic mechanisms rather than one single established pathway.

Acute CNS Toxicity

Because carbon disulfide is:

• Highly volatile
• Lipophilic
• Rapidly absorbed

high concentrations readily affect the CNS.

Acute exposure can produce a solvent-like syndrome:

CNS excitation/intoxication → CNS depression → coma

High-dose exposure can also produce:

• Respiratory compromise
• Seizures
• Paralysis

Chronic Neurotoxicity

The best-supported mechanism for chronic peripheral neuropathy involves:

CS₂ → dithiocarbamate protein adducts → protein cross-linking → neurofilament aggregation → impaired axonal transport → distal axonal degeneration

This produces a neurofilamentous distal axonopathy resembling that caused by n-hexane.

Additional proposed mechanisms include:

• Metal chelation
• Abnormal vitamin B6 metabolism
• Oxidative stress

Dopaminergic Effects

Carbon disulfide metabolites may interfere with catecholamine metabolism, including inhibition of:

Dopamine β-hydroxylase

which converts:

Dopamine → norepinephrine

This may contribute to some CNS and movement abnormalities.

Cardiovascular Toxicity

Chronic carbon disulfide exposure has been associated with:

• Coronary artery disease
• Atherosclerotic cardiovascular disease
• Elevated cardiovascular mortality in heavily exposed historical cohorts
• Possible lipid abnormalities

The 2025 ATSDR systematic review found moderate human evidence of cardiovascular effects from inhalational exposure.

Thus, the older concept that carbon disulfide causes vascular injury remains broadly valid, although the mechanism is more complex than simple direct endothelial toxicity.

Clinical Features

Acute Exposure

Mild–Moderate Exposure

Possible manifestations include:

• Headache
• Dizziness
• Lightheadedness
• Fatigue
• Weakness
• Nausea
• Vomiting
• Eye/nasal irritation
• Cough
• Dyspnea

Patients may appear:

• Euphoric
• Disinhibited
• Confused
• “Intoxicated”

similar to other volatile-solvent exposures.

Severe Acute Neurotoxicity

With increasing exposure:

• Agitation
• Delirium
• Psychosis
• Ataxia
• Tremor
• CNS depression
• Seizures
• Paralysis
• Coma

may occur.

Profound exposure can result in:

• Respiratory depression
• Hypoxia
• Cardiovascular collapse
• Death

Respiratory

Acute inhalation may cause:

• Cough
• Dyspnea
• Bronchospasm
• Wheezing
• Hypoxemia

Transient reductions in:

• Vital capacity
• Arterial oxygenation

have been documented after accidental inhalational exposures.

Severe respiratory compromise may require mechanical ventilation.

HEENT / Ocular

Acute exposure can cause:

• Lacrimation
• Conjunctival irritation
• Nasal irritation
• Throat irritation

Chronic exposure has been associated with retinal microvascular abnormalities and other ophthalmologic effects.

The 2025 ATSDR systematic review found moderate human evidence for ophthalmologic effects from chronic inhalational exposure.

Dermatologic

Liquid carbon disulfide can cause:

• Skin irritation
• Dermatitis
• Chemical injury after prolonged contact

More importantly:

Carbon disulfide can be systemically absorbed through skin.

Therefore, dermal contamination should not be treated as merely a local irritant exposure.

Gastrointestinal

Acute exposure may produce:

• Nausea
• Vomiting
• Abdominal discomfort

Chronic exposure has historically been associated with gastritis, although gastrointestinal findings are much less specific than neurologic and cardiovascular effects.

Cardiovascular

Acute high-level exposure may cause:

• Tachycardia
• Hypotension
• Cardiovascular instability

Chronic exposure is more clinically important and has been associated with:

• Atherosclerotic disease
• Coronary heart disease
• Possible hypertension
• Altered lipid homeostasis

Historical occupational cohorts found increased coronary mortality in heavily exposed workers.

Chronic Neurotoxicity

Peripheral Neuropathy

A major chronic manifestation is:

Distal symmetric sensorimotor polyneuropathy

Symptoms include:

• Paresthesias
• Distal numbness
• Burning sensations
• Muscle weakness
• Leg pain
• Gait difficulty
• Reduced reflexes

Nerve-conduction studies may show:

• Slowed conduction
• Axonal dysfunction
• Mixed axonal/demyelinating features

CNS / Neurobehavioral Effects

Chronic exposure may also produce:

• Irritability
• Mood disturbance
• Poor concentration
• Memory impairment
• Psychomotor slowing
• Tremor
• Encephalopathy
• Cerebellar dysfunction

Severe historical exposure has been associated with:

Parkinsonian or Parkinson-like movement abnormalities

ATSDR’s 2025 systematic review considers neurologic toxicity a known human health effect of carbon disulfide inhalation.

Renal and Hepatic Effects

Kidney and liver injury have been reported after substantial exposure.

Possible abnormalities include:

• Increased creatinine
• Proteinuria
• Abnormal liver enzymes

However, these are less characteristic than:

• CNS toxicity acutely
• Neurovascular toxicity chronically

NIOSH lists both the kidneys and liver among potential target organs.

Reproductive and Developmental Toxicity

The older claim that human surveillance definitively demonstrates increased congenital malformations is too strong.

Current ATSDR assessment is more cautious.

Male reproductive effects

Carbon disulfide is considered a suspected male reproductive toxicant based on:

• Inadequate human evidence
• Moderate animal evidence

Reported occupational effects have included:

• Reduced libido
• Erectile dysfunction
• Inconsistent sperm abnormalities

Female pregnancy outcomes

Human evidence for:

• Miscarriage
• Stillbirth
• Prematurity
• Congenital malformations

is inconsistent or inadequate.

Animal studies provide stronger evidence for developmental toxicity than the available human data.

Therefore:

Avoid unnecessary occupational carbon disulfide exposure during pregnancy, but do not state that congenital malformations are proven human effects.

Carcinogenicity

The older statement:

“Carbon disulfide is not carcinogenic.”

is too definitive.

Current OSHA chemical information lists the ACGIH classification as:

A4 — Not classifiable as a human carcinogen

This means:

Insufficient evidence to classify

—not proof that the substance cannot cause cancer.

An IARC advisory report noted that carbon disulfide had not previously undergone a formal IARC Monographs evaluation.

So the clinically appropriate wording is:

Carbon disulfide is not currently established as a human carcinogen; available evidence is insufficient for a definitive carcinogenic classification.

Diagnosis

Diagnosis depends heavily on the exposure history.

Ask about:

• Occupation
• Viscose/rayon work
• Rubber manufacturing
• Chemical production
• Solvent use
• Confined spaces
• Ventilation
• PPE
• Skin contact
• Duration and estimated concentration
• Whether coworkers are symptomatic

The combination of:

Industrial exposure + intoxication/CNS symptoms

suggests acute poisoning.

The combination of:

Long-term occupational exposure + distal neuropathy/neurobehavioral changes

should raise suspicion for chronic toxicity.

Differential Diagnosis

Acute altered mental status

Consider:

• Carbon monoxide
• Hydrogen sulfide
• Cyanide
• Organic solvent intoxication
• Asphyxiant gases
• Toxic alcohols
• Alcohol/sedative intoxication
• Hypoglycemia
• CNS infection
• Stroke

Chronic neuropathy

Consider:

• n-Hexane
• Lead
• Arsenic
• Thallium
• Mercury
• Diabetes
• Vitamin B12 deficiency
• Alcohol-associated neuropathy
• Hereditary neuropathy

Investigations

Acute Exposure

Testing should be guided by severity.

Consider:

• CBC
• Electrolytes
• Glucose
• BUN/creatinine
• Liver tests
• Blood gas
• Lactate
• Urinalysis

In severe exposure:

• Troponin
• Coagulation studies
• CK when seizures/immobility occur

A recent clinical review recommends organ-directed testing for pulmonary, cardiovascular, renal, and neurologic complications rather than relying on a specific CS₂ blood concentration.

ECG

Obtain an ECG in:

• Significant acute exposure
• Syncope
• Chest pain
• Hypotension
• Severe neurologic toxicity

Continuous monitoring is appropriate for critically ill patients.

Respiratory Assessment

For respiratory symptoms:

• Pulse oximetry
• Serial respiratory examination

Consider:

• Blood gas
• Chest radiograph

for:

• Hypoxemia
• Persistent cough
• Significant dyspnea
• Suspected aspiration/pneumonitis

Chronic Neurologic Evaluation

Depending on symptoms, consider:

• Detailed neurologic examination
• Electromyography
• Nerve conduction studies
• Neuropsychological testing

Nerve-conduction abnormalities can persist long after major exposure.

Biomonitoring

Urinary TTCA

The principal occupational biomarker is:

2-thiothiazolidine-4-carboxylic acid (TTCA)

measured in urine.

TTCA generally reflects recent carbon disulfide exposure and is typically obtained at the end of the work shift.

A 2024 NIOSH occupational report cites the current ACGIH biological exposure index:

Urinary TTCA = 0.5 mg/g creatinine at the end of shift

Important limitations

TTCA:

• Is an exposure biomarker, not a severity marker
• Does not directly diagnose acute poisoning
• Can have background contributions from nonoccupational sources
• Is less useful at very low-level exposure

Therefore:

Do not delay emergency treatment while waiting for TTCA.

Blood Carbon Disulfide

Blood or exhaled carbon disulfide measurement may be possible in specialized settings.

However:

• It is rapidly cleared
• Testing is not widely available
• Concentrations correlate poorly with clinical severity in routine practice

Thus, blood levels are generally not clinically useful for emergency treatment decisions.

Treatment

1. Rescuer Safety

Because carbon disulfide is:

Extremely flammable + volatile

rescuers should avoid:

• Sparks
• Flames
• Smoking
• Unprotected entry into confined or heavily contaminated spaces

Unknown/high-concentration environments require appropriate supplied-air respiratory protection.

NIOSH recommends positive-pressure SCBA or equivalent protection for IDLH conditions.

2. Remove From Exposure

For inhalation:

Move immediately to fresh air.

Terminate further occupational exposure.

Do not permit an unprotected rescuer to enter a contaminated confined space.

3. Airway and Breathing

Provide:

• Oxygen for hypoxemia
• Ventilatory support when needed

Intubate for:

• Severe CNS depression
• Inability to protect airway
• Respiratory failure
• Recurrent seizures

There is no role for a specific antidote in reversing CNS depression.

4. Bronchospasm

Treat bronchospasm with:

Inhaled β₂-agonist bronchodilator

such as:

• Albuterol/salbutamol

Other asthma-directed treatment may be used according to the clinical syndrome.

Routine corticosteroids are not established as a carbon-disulfide-specific antidotal treatment.

5. Dermal Decontamination

For liquid contamination:

• Remove contaminated clothing promptly
• Prevent ignition
• Wash exposed skin thoroughly with soap and water

NIOSH specifically recommends immediate soap washing.

Because CS₂ can be absorbed through skin, prompt removal is important.

6. Eye Exposure

Immediately irrigate exposed eyes with:

• Copious water
• Saline if available

Continue irrigation for at least approximately:

15 minutes

and reassess.

Persistent:

• Pain
• Redness
• Visual disturbance

requires further ocular evaluation.

NIOSH recommends immediate eye irrigation.

7. Ingestion

Do not induce vomiting.

Carbon disulfide is:

• Volatile
• CNS depressant at high doses

so vomiting can increase aspiration risk.

Rinse the mouth.

If the patient is awake and can swallow normally, limited oral dilution may be considered, but airway status takes priority.

Activated Charcoal

Older references recommend routine charcoal.

Modern general toxicology principles are more selective:

Activated charcoal should not be given routinely to every poisoned patient.

It can be considered after a recent potentially dangerous ingestion if:

• The substance is likely still in the GI tract
• The patient has an intact/protected airway
• Aspiration risk is acceptable

Because carbon disulfide itself may produce rapid neurologic deterioration, the risk-benefit balance should be individualized with poison-center/toxicology consultation.

Gastric Lavage

The older recommendation for routine nasogastric aspiration or lavage after ingestion is not contemporary routine practice.

Gastric lavage should only exceptionally be considered after:

• An immediately life-threatening ingestion
• Very early presentation
• Protected airway

and only after specialist toxicology input.

Routine lavage is not justified.

Antidote

There is no proven specific antidote for carbon disulfide poisoning.

Historical suggestions such as intravenous urea have no established clinical efficacy and should not be used routinely.

Seizures

First-line:

Benzodiazepines

Examples:

• Lorazepam
• Midazolam
• Diazepam

If refractory:

• Phenobarbital
• Propofol in an intubated patient

may be considered according to standard toxicologic seizure management.

Also correct:

• Hypoxia
• Hypoglycemia
• Electrolyte abnormalities

Hypotension

Treat according to contemporary shock principles:

• Isotonic crystalloid when fluid responsive
• Vasopressor for persistent shock

Norepinephrine is generally an appropriate first-line vasopressor for persistent hypotension.

The old preference for dopamine and Trendelenburg positioning is outdated.

Enhanced Elimination

There is no established role for:

• Hemodialysis
• Hemoperfusion
• Forced diuresis

as routine toxin-removal therapies.

Carbon disulfide rapidly distributes and is metabolized; management is principally supportive.

Dialysis should be used only if a conventional indication develops from organ failure.

Chronic Toxicity – Management

The most important intervention is:

Stop further exposure

Occupational-health involvement is essential.

Management may include:

• Neurology review
• Nerve conduction testing
• Cardiovascular risk assessment
• Blood pressure monitoring
• Lipid profile
• Ophthalmologic evaluation when indicated
• Renal assessment
• Workplace exposure investigation

Engineering controls and respiratory/skin protection are more important than pharmacologic treatment.

Recovery From Neuropathy

The older text states that neuropathy and encephalopathy do not improve after exposure cessation.

That is too absolute.

Recovery varies according to exposure intensity.

Lower-level nerve conduction abnormalities may improve after removal from exposure, while severe poisoning can leave abnormalities for years.

Therefore:

Mild/subclinical neuropathy may be reversible; severe axonal injury may be prolonged or incomplete.

Occupational Exposure Standards

The older ACGIH limit of 10 ppm is outdated.

NIOSH REL

Current NIOSH:

TWA = 1 ppm (3 mg/m³)

STEL = 10 ppm (30 mg/m³)

with a skin notation.

NIOSH IDLH

500 ppm

OSHA

Current federal OSHA general-industry limits remain:

TWA = 20 ppm

Ceiling = 30 ppm

Maximum peak = 100 ppm for 30 minutes

Important

The OSHA limit is substantially less protective than the current NIOSH recommended exposure limit.

Current ACGIH Information

A recent NIOSH occupational-health evaluation cites:

ACGIH TLV-TWA = 1 ppm

with:

Urinary TTCA BEI = 0.5 mg/g creatinine at end of shift

Thus, the historical 10-ppm ACGIH TLV should no longer be used.

Pregnancy

Human reproductive data are limited and inconsistent.

Current evidence does not justify saying that carbon disulfide definitively causes human birth defects.

ATSDR’s current assessment is:

• Human developmental evidence: inadequate
• Animal developmental evidence: moderate
• Developmental toxicity remains a suspected hazard

Pregnant workers should minimize exposure according to occupational-health guidance.

For acute maternal poisoning:

Maternal airway, oxygenation, and circulation take priority.

Monitoring

Acute Exposure

Symptomatic patients may require:

• Continuous pulse oximetry
• Cardiac monitoring
• Serial neurologic examinations
• Blood pressure monitoring

Repeat laboratory testing according to:

• Respiratory compromise
• Renal injury
• Hepatic injury
• Shock
• Seizures

Admission

Hospital admission is appropriate for:

• Persistent CNS depression
• Significant confusion
• Seizure
• Hypoxemia
• Bronchospasm not rapidly resolving
• Respiratory distress
• Hypotension
• Significant ingestion
• Evidence of organ injury

Patients with:

• Coma
• Respiratory failure
• Recurrent seizures
• Hemodynamic instability

require ICU-level care.

Observation / Disposition

The historical fixed:

“4–6 hours then discharge”

should not be applied automatically.

A brief, mild inhalational exposure may permit discharge after an appropriate symptom-free observation period when:

• Neurologic examination is normal
• Oxygenation is normal
• Vital signs are stable
• No significant ingestion occurred
• No important coexposure exists

Higher-concentration, intentional, confined-space, or symptomatic exposures warrant longer observation.

Prognosis

Acute Exposure

Patients with mild acute exposure generally recover after removal from the source.

Severe exposure can lead to:

• Coma
• Respiratory failure
• Hypoxic brain injury
• Death

Long-term outcome depends largely on:

• Exposure magnitude
• Duration
• Severity of neurologic injury
• Hypoxic complications

Chronic Exposure

Persistent sequelae may include:

• Peripheral neuropathy
• Cognitive/neurobehavioral impairment
• Parkinson-like abnormalities
• Retinal vascular changes
• Cardiovascular disease

Neurologic recovery can be:

• Complete
• Partial
• Very prolonged

depending on severity.

Important Pitfalls

1. Calling carbon disulfide a gas

At ordinary room temperature:

CS₂ is a highly volatile liquid that readily generates toxic vapor.

2. Ignoring skin absorption

NIOSH assigns a skin notation.

Dermal contamination can add materially to systemic exposure.

3. Forgetting the fire/explosion hazard

Carbon disulfide has an exceptionally low flash point.

Eliminate ignition sources before decontamination/rescue.

4. Relying on odor

The smell is not a safe exposure monitor.

Industrial grades can smell different, and dangerous exposure should be assessed by environmental monitoring rather than odor perception.

5. Treating TTCA as a diagnostic toxin level

TTCA measures recent exposure, not clinical poisoning severity.

Current ACGIH BEI:

0.5 mg/g creatinine at end of shift

6. Using the old ACGIH 10-ppm limit

Current ACGIH/NIOSH guidance is much lower:

1 ppm TWA

7. Calling carbon disulfide definitively noncarcinogenic

ACGIH currently classifies it:

A4 — not classifiable as a human carcinogen

which is not equivalent to proven absence of carcinogenicity.

8. Missing chronic neuropathy

A patient with:

• Distal paresthesias
• Weakness
• Reduced reflexes
• Gait difficulty

who works in rayon/rubber/chemical production should prompt an occupational-exposure history.

9. Assuming chronic neuropathy never improves

Some lower-level effects are reversible after exposure cessation, while severe axonal injury may persist for years.

10. Overstating pregnancy risk

Older reports suggested congenital anomalies, but current human evidence is insufficient to establish a causal developmental effect.

Animal evidence remains concerning.

High-Yield Toxicology Pearls

Carbon disulfide = acute solvent neurotoxicity + chronic neurovascular toxicity

Think:

Industrial worker + headache/dizziness/intoxication → severe exposure can cause seizure/coma

and:

Long-term rayon/industrial exposure + distal neuropathy ± neurobehavioral/cardiovascular disease

Key points:

• Carbon disulfide is CS₂
• It is a highly volatile liquid, not simply a gas
• Extremely flammable/explosive
• Major route: inhalation
• Significant dermal absorption also occurs
• Acute toxicity:
• Headache
• Dizziness
• Nausea
• Intoxication/confusion
• Bronchospasm
• CNS depression
• Seizures
• Coma
• Chronic hallmark: distal sensorimotor polyneuropathy
• Chronic neurotoxicity involves neurofilament protein cross-linking and axonal degeneration
• Parkinson-like and neurobehavioral effects may occur
• Chronic exposure is associated with cardiovascular disease
• TTCA is the main urinary exposure biomarker
• Current ACGIH TTCA BEI: 0.5 mg/g creatinine at end of shift
• TTCA indicates exposure, not poisoning severity
• No specific antidote
• Main acute treatment:
• Remove from exposure
• Oxygen/ventilation as needed
• Benzodiazepines for seizures
• Supportive hemodynamic care
• Remove contaminated clothing
• Wash skin promptly with soap and water
• Irrigate eyes immediately
• Do not induce vomiting
• Activated charcoal is selective, not routine
• Routine gastric lavage is obsolete
• No established role for hemodialysis to remove CS₂
• NIOSH REL:
• 1 ppm TWA
• 10 ppm STEL
• NIOSH IDLH: 500 ppm
• OSHA PEL remains:
• 20 ppm TWA
• 30 ppm ceiling
• 100 ppm for 30-min maximum peak
• ACGIH classification: A4, not classifiable as a human carcinogen
• Chronic neurologic effects may improve after exposure cessation, but severe neuropathy can persist for years