Safety Data Sheet (SDS) Section 11 contains the toxicological information that forms the scientific foundation for all hazard classifications and control measures in the workplace. Understanding this section is essential because it translates complex chemical science into actionable safety decisions that protect workers’ health. 

Section 11 serves as the backbone of hazard communication, providing the toxicity data that supports the warning labels and pictograms appearing on chemical containers. Workers and EHS leaders who can effectively interpret Section 11 gain the ability to anticipate risks, select appropriate personal protective equipment (PPE), and implement engineering controls before exposure incidents occur. 

The purpose of this article is to equip workplace safety professionals and workers with practical knowledge to read, interpret, and act upon the toxicological information in Section 11, ultimately enabling safer chemical handling and reduced occupational health risks. 

What SDS Section 11 Contains (OSHA & GHS Overview) 

Toxicological information refers to the scientific data about how substances harm living organisms, including the dose levels at which toxicity occurs, the routes through which exposure happens, and the health effects that result from exposure. This data forms the basis for classifying chemicals as hazardous under the Globally Harmonized System (GHS) and OSHA regulations. 

Under OSHA’s Hazard Communication Standard, manufacturers must include all relevant toxicological data from scientific literature and animal testing studies. While certain data fields are mandatory (such as acute toxicity values and target organ effects), other information is optional if no studies exist or data is proprietary. 

Key Toxicology Elements Workers Should Focus On 

1. Routes of Exposure

Exposure routes describe how a chemical enters the body and directly determine which control measures are most effective. 

• Inhalation: Workers breathe in chemical vapors, gases, mists, or dust. This is the most common route in industrial settings. Section 11 will specify if the chemical is hazardous by inhalation and the concentration levels that cause concern. High inhalation toxicity signals the need for respiratory protection and ventilation systems. 

• Skin Contact: Chemicals absorbed through or that damage the skin represent a significant workplace hazard. Section 11 notes whether skin contact causes irritation, allergic reactions, or systemic toxicity (where the chemical enters the bloodstream). This determines glove selection and protective clothing requirements. 

• Eye Contact: Direct eye exposure can cause temporary irritation or permanent blindness, depending on chemical corrosivity. Section 11 classifies eye hazards as irritating or corrosive. Corrosive chemicals require eye wash stations and immediate medical attention protocols. 

• Ingestion: Although less common in typical industrial work, ingestion occurs through contaminated food or inadequate hand washing. Section 11 specifies LD50 values (oral toxicity) and whether the chemical is harmful or fatal if swallowed. 

2. Symptoms of Exposure

Recognizing exposure symptoms enables early intervention and prevents serious injury escalation. 

• Immediate (Acute) Symptoms: These appear within minutes to hours of exposure—burning in throat, dizziness, nausea, skin redness, or eye pain. Section 11 lists acute effects prominently because workers need to recognize them in real time and seek first aid immediately. 

• Delayed (Chronic) Symptoms: These develop after weeks, months, or years of repeated low-level exposure. Examples include respiratory disease, organ damage, nervous system effects, or cancer. Section 11 describes chronic effects separately because they require different intervention strategies: long-term medical monitoring, exposure elimination, and preventive controls rather than immediate first aid. 

Why symptom recognition matters: Workers exposed to acute irritants without protection can develop chemical burns or respiratory distress before help arrives. For chronic hazards, workers often don’t realize they’re being harmed until irreversible damage occurs, making symptom tracking and medical surveillance critical for early detection. 

3. Numerical Toxicity Data

Toxicity numbers quantify how poisonous a substance is and enable comparison across different chemicals. 

• LD50 (Lethal Dose 50%): This is the amount of a chemical that causes death in 50% of test animals (usually rats) when administered in a single dose. LD50 is expressed in milligrams of chemical per kilogram of body weight (mg/kg). A lower LD50 number indicates higher toxicity. For example, LD50 of 50 mg/kg is far more toxic than 5,000 mg/kg. 

• LC50 (Lethal Concentration 50%): This is the airborne concentration that causes death in 50% of test animals after a 4-hour exposure. LC50 measures inhalation toxicity and is expressed in parts per million (ppm) or mg/m³. Lower LC50 values signal greater respiratory hazard. 

• ATE (Acute Toxicity Estimate): Used for mixtures when component toxicity data isn’t fully available, ATE allows manufacturers to estimate mixture toxicity based on ingredient data. Workers need to know that ATE values follow the same interpretation as LD50/LC50. 

• Toxicity Classification by Hazard Category: Your Content Goes Here

4. Acute Health Effects

Acute effects represent immediate dangers from single exposure incidents—chemical burns, respiratory distress, temporary blindness, or central nervous system effects. Section 11 lists acute hazards prominently because they require emergency response training and immediate first aid. Examples include: 

• Skin burns and chemical irritation from corrosive acids or alkalis 

• Respiratory irritation, coughing, or difficulty breathing from irritant gases 

• Dizziness, drowsiness, or headache from solvent vapors 

• Eye damage or temporary vision loss from splashing 

• Nausea or vomiting from ingestion of toxic substances 

5. Chronic Health Effects

Chronic effects accumulate over repeated or prolonged exposure and often go unrecognized until serious damage occurs. Critical chronic health effects include: 

• Organ Damage: Liver or kidney damage from repeated solvent exposure 

• Respiratory Issues: Occupational asthma, chronic bronchitis, or lung fibrosis from dust or chemical inhalation 

• Skin Sensitization: Progressive allergic reactions that worsen with each exposure 

• Nervous System Effects: Memory loss, tremors, or behavioral changes from neurotoxic compounds 

Chronic effects require proactive monitoring through medical surveillance programs because workers won’t experience immediate warning symptoms. 

6. Carcinogenicity Information

Carcinogenicity classifications indicate whether a chemical can cause cancer. Different organizations use different classification systems: 

• OSHA Classification: Labels chemicals as Group A (human carcinogen), Group B (probable human carcinogen), or Group C (possible human carcinogen). 

• IARC (International Agency for Research on Cancer): Uses Group 1 (carcinogenic to humans), Group 2A (probably carcinogenic), Group 2B (possibly carcinogenic), or Group 3 (not classifiable). 

• NTP (National Toxicology Program): Designates chemicals as Known Carcinogens or Reasonably Anticipated to be Carcinogens. 

“Suspected carcinogen” means sufficient animal evidence exists to warrant concern, but human data is limited. “Known carcinogen” means strong human epidemiological evidence that exists linking chemicals to cancer. Known carcinogens require the most stringent controls: engineering elimination, minimal exposure policies, and medical surveillance including baseline cancer screening. 

7. Mutagenicity & Genotoxicity

Mutagenicity indicates the chemical can damage DNA and cause genetic mutations. Genotoxicity is a broader term encompassing any damage to genetic material. These hazards are serious because DNA damage can trigger cancer development, reproductive problems, or heritable genetic disorders. Section 11 lists any positive test results, which signal the need for exposure minimization and reproductive risk assessment, especially for workers of childbearing age. 

8. Reproductive Toxicity

Reproductive toxicity affects fertility, sexual function, or fetal development. Section 11 differentiates between: 

• Effects on Fertility: The chemical reduces the ability to conceive or causes impotence 

• Developmental Toxicity: The chemical causes birth defects, miscarriage, or fetal death in exposed mothers 

• Lactational Effects: The chemical passes into breast milk and harms nursing infants 

This information is critical for pregnant workers, workers planning pregnancy, or those of childbearing age. Employers may need to restrict exposure for certain workers or provide alternative job assignments during pregnancy. 

9. Sensitization

Sensitization means repeated exposure creates allergic reactions in susceptible workers. Two types appear in Section 11: 

• Respiratory Sensitizers: Chemicals that trigger occupational asthma after exposure builds up. Once sensitized, workers experience asthma symptoms at very low exposure levels, sometimes making continued employment in the role impossible. 

• Skin Sensitizers: Chemicals causing allergic contact dermatitis. After sensitization, even brief contact triggers itching, redness, and blistering. The reaction worsens with each subsequent exposure. 

10. STOT (Specific Target Organ Toxicity)

STOT hazard classifications indicate which organs are damaged by the chemical: 

• STOT–Single Exposure: Organ damage occurs from a brief, high-level exposure incident. Example: a solvent exposure causing dizziness and liver stress after one accident. 

• STOT–Repeated Exposure: Organ damage accumulates from regular, low-level exposure over weeks or months. Example: chronic kidney disease in workers exposed to heavy metals throughout their career. 

Section 11 specifies the target organ (liver, kidneys, nervous system, lungs) so that workers and physicians can implement organ-specific medical monitoring. 

11. Aspiration Hazard

Aspiration hazard indicates that liquids, when ingested or aspirated into the lungs, cause severe pneumonia and lung damage. Hydrocarbons are the most common aspiration hazards. Even small amounts entering the lungs during vomiting or choking can cause chemical pneumonitis. Section 11 marks aspiration hazards clearly because they require special first aid protocols—do not induce vomiting, seek immediate medical attention, and monitor respiratory function. 

How Section 11 Connects to Real Chemical Health Risks 

Section 11 toxicological data directly drive workplace safety decisions: 

• Health Risk Classification: The toxicity levels in Section 11 determine whether a chemical is labeled as Danger or Warning, and which pictograms appear on containers. 

• PPE Selection: Skin absorptivity and dermal toxicity data determine glove material and thickness. Inhalation LC50 values determine respirator cartridge type and protection factor. Eye hazard classification specifies whether goggles or face shields are required. 

• Ventilation Requirements: High inhalation toxicity and vapor pressure require local exhaust ventilation or fume hoods. Low inhalation toxicity may require only general dilution ventilation. 

• Exposure Limits: OSHA PEL and ACGIH TLV values are derived from Section 11 toxicology data. These limits represent the maximum allowable exposure concentrations during an 8-hour workday. 

• Emergency Response Protocols: High acute toxicity triggers first aid protocols, poison control notification, and medical surveillance. Carcinogens and reproductive hazards require incident reporting and medical follow-up. 

Understanding Toxicity Values and What They Mean for Workers 

High vs Low Toxicity 

Toxicity strength is counterintuitive: smaller LD50/LC50 numbers equal higher toxicity. An LD50 of 10 mg/kg is far more toxic than 10,000 mg/kg. The following ranges provide practical interpretation: 

Species Used in Toxicology Tests 

Manufacturers conduct toxicity tests primarily on rats, mice, and rabbits because their physiological systems resemble human systems. However, differences exist rats may metabolize chemicals differently than humans, and test doses are much higher than typical workplace exposures. Section 11 notes when human data is available (which is rare and valuable). 

Workers should recognize that animal-derived toxicity values provide directional information but aren’t perfectly predictive for humans. This is why chronic health effects and medical surveillance are so important—they capture actual human responses that may differ from animal models. 

Dose-Response Relationship 

The principle “dose makes the poison” reflects a fundamental toxicology truth: toxicity depends on exposure amount and frequency, not just substance presence. A substance safe at one dose becomes hazardous at higher doses. Section 11 data reflect specific dose levels, so comparison to actual workplace exposure levels (from Section 8) is essential for risk assessment. 

How to Identify High-Risk Chemicals Using Section 11 

Red flags indicating severe hazards requiring heightened controls include: 

• Acute Toxicity Category 1, 2, or 3 (especially for inhalation) 

• Carcinogenicity classifications (OSHA Group A/B, IARC Group 1/2A) 

• Mutagenicity or Genotoxicity findings 

• Reproductive Toxicity affecting fertility or fetal development 

• STOT–Repeated Exposure classifications indicating organ damage 

• Respiratory or skin sensitization potential 

• High dermal absorption and skin toxicity 

Chemicals with multiple hazards from this list require medical surveillance programs including baseline health assessments, periodic medical exams, and biological monitoring when applicable. 

How to Compare Section 11 Data to Exposure Limits 

1. Linking Section 11 to Section 8 (Exposure Controls/PPE)

Section 8 of the SDS (Exposure Controls and Personal Protective Equipment) should reflect the hazards identified in Section 11. High inhalation toxicity from Section 11 should correlate with respiratory protection requirements in Section 8. Skin sensitization should trigger chemical-resistant glove recommendations. Target organ toxicity should drive the selection of protective clothing. 

When Section 11 indicates severe hazards, but Section 8 recommends minimal PPE, this inconsistency signals incomplete hazard assessment and requires further investigation. 

2. Exposure Limits Reference

Three major organizations establish occupational exposure limits based on toxicological data: 

Limit Type	Organization	Purpose
OSHA PEL	U.S. Department of Labor	Legally enforceable 8-hour time-weighted average
ACGIH TLV	American Conference of Governmental Industrial Hygienists	Professional consensus standard; more stringent than PEL
NIOSH REL	National Institute for Occupational Safety and Health	Research-based recommendation; strictest level

When Section 11 describes a chemical as highly toxic, but no exposure limit exists (common for newer chemicals), this absence doesn’t indicate safety—it means toxicological evidence is insufficient or incomplete. In such cases, ALARA (As Low As Reasonably Achievable) principles apply, and engineering controls should eliminate or minimize exposure. 

Real-World Scenarios to Demonstrate Section 11 Interpretation 

Scenario 1: Solvent with Low Flash Point & High Inhalation Toxicity 

Section 11 shows LC50 of 500 ppm with acute respiratory irritation. Interpretation: The chemical is volatile and readily inhaled. Response: Implement local exhaust ventilation, select respiratory protection rated for organic vapors (cartridge type requirement), establish monitoring to ensure ventilation adequacy, and train workers on vapor hazards. 

Scenario 2: Skin Sensitizer Used Daily 

Section 11 indicates skin sensitization potential with repeated contact causing allergic dermatitis. Interpretation: Sensitization increases with exposure frequency. Response: Provide nitrile or chemical-resistant gloves with proper changeout protocol, implement skin care training (wash hands with appropriate cleaners), establish medical baseline documentation, and monitor workers for rash development. 

Scenario 3: Carcinogenic Dust in Manufacturing 

Section 11 shows IARC Group 1 carcinogen classification with inhalation exposure route. Interpretation: Breathing the dust poses long-term cancer risk. Response: Eliminate with safer substitutes if possible; otherwise, implement closed systems, local exhaust ventilation, respiratory protection (including fit testing), establish respiratory medical surveillance including baseline lung function testing, and limit worker exposure duration. 

Scenario 4: Hydrocarbon With Aspiration Hazard 

Section 11 notes aspiration hazard classification with high viscosity. Interpretation: Swallowing or inhaling during handling causes severe lung damage. Response: Implement strict no-eating policies in work areas, provide training on aspiration first aid (don’t induce vomiting), ensure immediate medical response capability, and establish incident reporting protocols. 

Common Mistakes Workers Make When Reading Section 11 

Workers often misinterpret Section 11 in ways that compromise safety: 

• Ignoring chronic effects because symptoms are not immediate: A chemical causing liver damage after years of exposure receives less attention than one causing skin rashes. However, organ damage is often irreversible, making chronic hazard recognition and prevention essential. 

• Misinterpreting LD50 values: Thinking “LD50 of 1,000 mg/kg” means the chemical is safe, when in fact this represents moderate toxicity. Comparison to reference toxins (table salt LD50 ≈ 3,000 mg/kg) provides context. 

• Overlooking sensitization data: Workers don’t realize that sensitization increases with exposure, meaning the first exposure may cause no symptoms, but the fifth causes severe allergic reactions. Once sensitized, workers become hyper-reactive to extremely low exposures. 

• Assuming “no data available” means “safe”: Missing toxicological data usually indicates whether the chemical is new or poorly studied, not that it’s safe. Precautionary measures remain essential. 

• Failing to compare Section 11 to label pictograms: The pictograms on chemical containers summarize Section 11 hazards visually. Discrepancies between pictograms and Section 11 content indicate labeling errors requiring manufacturer notification. 

 

What Manufacturers Must Ensure in Section 11 

Manufacturers have regulatory obligations to ensure Section 11 accuracy: 

• Toxicity data must reflect the most current scientific literature and testing results 

• When new hazard information emerges, manufacturers must update Section 11 and notify users 

• Section 11 classifications must align exactly with Section 2 (Hazard Identification) classifications 

• Acute and chronic risks must be clearly distinguished to prevent misinterpretation 

• Missing data must be explicitly noted, not implied as safe 

 

When to Seek Expert Help 

Beyond basic Section 11 interpretation, specialized expertise is warranted when: 

• Complex Mixtures: Chemicals containing multiple hazardous ingredients with conflicting data require industrial hygienist assessment to determine overall mixture toxicity 

• Limited Toxicological Studies: Newly developed chemicals or those with sparse research data require precautionary approaches beyond standard interpretation 

• Carcinogens or Reproductive Hazards: Legal and medical specialists should guide exposure minimization, medical surveillance program design, and worker notification 

• OSHA/NIOSH Interpretation Uncertainties: Ambiguous regulatory guidance requires consultation with occupational safety attorneys or certified industrial hygienists 

Practical Checklist for Reading SDS Section 11 

Use this checklist when evaluating a new chemical: 

Conclusion 

Section 11 of the Safety Data Sheet contains the scientific foundation for all workplace chemical safety decisions. The toxicological information in this section translates into real-world protection strategies: the type of gloves workers wear, the ventilation systems protecting breathing zones, the medical monitoring programs safeguarding long-term health, and the emergency protocols saving lives in accident scenarios. 

Workers and EHS teams who understand Section 11 gain the ability to anticipate hazards, communicate risks effectively, and implement controls that prevent both acute injuries and chronic occupational diseases. This knowledge is not merely academic—it represents the difference between chemical safety as abstract compliance and chemical safety as lived workplace reality. 

Proactive training on Section 11 interpretation and regular SDS review as products and processes change represent investments in occupational health that protect workers, reduce liability, and strengthen organizational safety culture. The time spent understanding toxicological information today prevents the healthcare costs and human suffering of occupational disease tomorrow.