Toxicology Reference · CIH · CRSP · CRST

Published July 30, 2026 · Kevin L., CRSP, CRST · Companion to the CIH Study Journal

Industrial Toxicology Reference

A quick-recognition reference table built while working through CIH Chapter 4 (Toxicology) — the chapter with no shortcuts, just memorization. 69 substances across 8 chemical families — toxic metals, organic solvents, alcohols & glycols, aldehydes & ketones, pesticides, toxic gases, simple asphyxiants, and fibers — each entry listing appearance/odor, physical state, primary exposure route, acute effects, chronic (long-term) effects, and the common industries where exposure occurs, plus a set of mnemonics for the substances that come up again and again. Useful as general industrial toxicology recall practice, not only for a specific exam.

How to use this page

Toxicology chapters are dense and mostly non-negotiable memorization — there's no formula to reason your way to "mercury causes tremors." This page exists to make that recall faster, not to replace the primary reference.

Built for CIH, but just as relevant for CRSP and CRST. This same content maps onto CRSP's chemical hazard (HRIA6), physical hazard (HRIA8), and biological hazard (HRIA5) competencies, and CRST's HIRAC14 (gases, vapours, solvents, fumes, dusts) and HIRAC15 (physical hazards) domains. The exam names differ; the underlying toxicology doesn't.
Chronic effects are in red in each table — these are usually what gets tested, since acute effects are often more intuitive (irritation, dizziness) while chronic effects are the "gotcha" pairing (e.g. Cadmium → kidneys, not lungs, despite inhalation being the exposure route).
This is a recognition aid, not a toxicology textbook. Values, effects, and classifications are summarized for quick recall — always verify against ACGIH TLVs/BEIs, SDS/GHS data, and your primary IH reference before applying any of this in practice.
Organized by chemical family — jump to any section below, or scroll straight through.

📖 Recommended Reference

2025 TLVs and BEIs® — ACGIH

The authoritative source for exposure limits behind every substance on this page

View on Amazon →

As an Amazon Associate, SPEP earns from qualifying purchases.

01 Toxic Metals & Metallic Compounds

The heaviest-memorization group — appearance and odor rarely help, so pair each metal to its signature chronic effect.

Chemical	Appearance	State	Main Route	Acute Effects	Chronic Effects	Common Industries
Mercury (Hg)	Silver liquid, odorless	Liquid	Inhalation (vapor), skin, ingestion	Pneumonitis, cough, chest pain	Tremors, erethism, memory loss, kidney damage	Chlor-alkali plants, mining, dentistry, fluorescent lamps, gold extraction
Methyl Mercury	Colorless, odorless	Liquid	Ingestion	GI upset	Severe neurotoxicity, fetal brain damage	Seafood contamination, chemical manufacturing
Lead	Bluish-gray, odorless	Solid	Inhalation, ingestion	Abdominal pain, fatigue	Anemia, neuropathy (wrist drop), kidney disease, reproductive toxicity	Battery manufacturing, smelting, demolition, shooting ranges
Arsenic	Gray metallic, odorless	Solid	Inhalation, ingestion	Vomiting, diarrhea, shock	Skin cancer, lung cancer, neuropathy	Smelting, mining, wood preservatives
Cadmium	Silver-white, odorless	Solid	Inhalation	Metal fume fever, pneumonitis	Kidney damage, osteoporosis, lung cancer	Battery manufacturing, electroplating, welding
Hexavalent Chromium (Cr VI)	Yellow-orange compounds, odorless	Solid	Inhalation, skin	Skin burns, nasal irritation	Lung cancer, nasal septum perforation	Stainless steel welding, chrome plating, pigments
Nickel	Silver-white, odorless	Solid	Inhalation, skin	Dermatitis	Lung cancer, nasal cancer	Electroplating, alloy production
Nickel Carbonyl	Colorless, musty	Gas	Inhalation	Delayed pulmonary edema	Lung damage	Nickel refining
Beryllium	Steel gray, odorless	Solid	Inhalation	Pneumonitis	Chronic Beryllium Disease (CBD), lung cancer	Aerospace, nuclear, electronics
Cobalt	Gray, odorless	Solid	Inhalation	Asthma	Cardiomyopathy, pulmonary fibrosis	Hard metal manufacturing
Manganese	Gray, odorless	Solid	Inhalation	Irritation	Parkinson-like syndrome (Manganism)	Welding, mining
Aluminum	Silver, odorless	Solid	Dust inhalation	Irritation	Pulmonary fibrosis (rare)	Aluminum smelting
Antimony	Silvery, odorless	Solid	Inhalation	Eye irritation	Pneumoconiosis	Flame retardants
Stibine	Colorless, garlic	Gas	Inhalation	Massive hemolysis	Kidney failure	Semiconductor manufacturing
Selenium	Gray, garlic breath	Solid	Inhalation, ingestion	GI irritation	Hair loss, nail changes	Electronics
Thallium	Bluish-white, odorless	Solid	Ingestion, inhalation	GI symptoms	Peripheral neuropathy, alopecia	Electronics
Vanadium Pentoxide	Yellow-orange powder, odorless	Solid	Inhalation	Respiratory irritation	Chronic bronchitis	Oil-fired boilers
Uranium	Silver-gray, odorless	Solid	Inhalation	Kidney toxicity	Radiation risk	Nuclear industry

02 Organic Solvents

Almost all colorless liquids with a sweet or aromatic odor and CNS depression as the acute effect — the chronic effect is what separates them.

Chemical	Appearance/Odor	Entry Route	Acute Effects	Chronic Effects	Common Industries
Benzene	Colorless, sweet	Inhalation	Dizziness	Leukemia	Petrochemical
Toluene	Colorless, sweet	Inhalation	CNS depression	Hearing loss, neurotoxicity	Paints
Xylene	Colorless, sweet	Inhalation	Headache	Liver/kidney effects	Paints
Ethylbenzene	Colorless, aromatic	Inhalation	Dizziness	Hearing loss	Fuel
Styrene	Colorless, sweet	Inhalation	Irritation	Peripheral neuropathy	Fiberglass
n-Hexane	Colorless, gasoline-like	Inhalation	CNS depression	Peripheral neuropathy	Printing
Carbon Tetrachloride	Colorless, sweet	Inhalation	CNS depression	Liver necrosis	Chemical manufacturing
Chloroform	Colorless, sweet	Inhalation	Anesthesia	Liver damage	Labs
Methylene Chloride	Colorless, sweet	Inhalation	Dizziness	Possible cancer	Paint stripping
Trichloroethylene	Colorless, sweet	Inhalation	Narcosis	Kidney cancer	Degreasing
Tetrachloroethylene	Colorless, ether-like	Inhalation	CNS depression	Liver damage	Dry cleaning
Vinyl Chloride	Colorless, mild sweet	Inhalation	Dizziness	Liver angiosarcoma	PVC manufacturing

03 Alcohols & Glycols

Small family, easy to separate: methanol targets the eyes, the glycols target the kidneys.

Chemical	Odor	State	Acute Effect	Chronic Effect	Industries
Methanol	Alcohol	Liquid	Blindness, acidosis	Optic nerve damage	Solvents
Ethanol	Alcohol	Liquid	Intoxication	Liver disease	Beverage, sanitizer
Isopropanol	Alcohol	Liquid	CNS depression	Dermatitis	Cleaning
Ethylene Glycol	Sweet	Liquid	Kidney failure	Renal damage	Antifreeze
Propylene Glycol	Nearly odorless	Liquid	Low toxicity	Minimal	Food, pharma

04 Aldehydes & Ketones

Formaldehyde is the odd one out here — a known carcinogen where the others are mainly narcotic/dermatitis risks.

Chemical	Odor	State	Acute Effect	Chronic Effect	Industries
Formaldehyde	Pungent	Gas	Eye irritation	Nasal cancer	Resins, labs
Acrolein	Burning	Liquid	Pulmonary irritation	Airway disease	Combustion
MEK (Methyl Ethyl Ketone)	Sweet	Liquid	CNS depression	Dermatitis	Paint
MnBK (Methyl n-Butyl Ketone)	Sweet	Liquid	Dizziness	Peripheral neuropathy	Solvents

05 Pesticides

Organophosphates (Parathion, Malathion) share the same mechanism — cholinesterase inhibition — while the organochlorines (DDT, Chlordane, Aldrin) act on the CNS directly.

Chemical	Appearance	Major Toxic Effect	Chronic Effect	Industries
Parathion	Brown liquid	Cholinesterase inhibition	Neuropathy	Agriculture
Malathion	Amber liquid	Cholinergic symptoms	Lower chronic toxicity	Agriculture
DDT	White crystals	Tremors	Possible carcinogen	Historical
Chlordane	Amber liquid	CNS stimulation	Liver toxicity	Termite control
Aldrin	White crystals	Seizures	Liver toxicity	Historical
DBCP	Colorless liquid	Eye irritation	Male infertility	Agriculture

📖 Study Reference

2025 TLVs and BEIs® — ACGIH

Exposure limits & Biological Exposure Indices for every substance above

View on Amazon →

As an Amazon Associate, SPEP earns from qualifying purchases.

06 Toxic Gases

Density relative to air matters operationally — heavier-than-air gases pool in low-lying and confined spaces.

Gas	Color/Odor	Density vs. Air	Acute Effect	Chronic Effect	Industries
Carbon Monoxide	Colorless, odorless	Slightly lighter	Hypoxia	Neuro/cardiac injury	Combustion
Hydrogen Sulfide	Rotten eggs	Heavier	Respiratory paralysis	Neurological effects	Oil & gas
Hydrogen Cyanide	Bitter almonds	Slightly lighter	Cellular hypoxia	Neurological effects	Electroplating
Ammonia	Sharp, colorless	Lighter	Airway burns	Bronchitis	Refrigeration
Chlorine	Green-yellow, bleach	Heavier	Pulmonary edema	RADS	Water treatment
Sulfur Dioxide	Colorless, burning	Heavier	Bronchospasm	Bronchitis	Smelters
Nitrogen Dioxide	Brown-red, acrid	Heavier	Pulmonary edema	Bronchiolitis	Welding
Ozone	Pale blue, electrical	Heavier	Chest tightness	Reduced lung function	UV/welding
Phosgene	Colorless, fresh-cut hay	Heavier	Delayed pulmonary edema	Lung disease	Chemical manufacturing

07 Simple Asphyxiants

Not toxic by chemical action — the hazard is oxygen displacement (or explosion risk for the flammable ones). Colorless and odorless, which is exactly what makes them dangerous.

Gas	Color/Odor	Hazard	Industries
Nitrogen	Colorless, odorless	Oxygen displacement	Confined spaces
Argon	Colorless, odorless	Oxygen displacement	Welding
Helium	Colorless, odorless	Oxygen displacement	Cryogenics
Carbon Dioxide	Colorless, odorless	Hypercapnia	Beverage plants
Hydrogen	Colorless, odorless	Explosion/asphyxiation	Refineries
Methane	Colorless, odorless	Explosion/asphyxiation	Natural gas
Ethane	Colorless, odorless	Explosion/asphyxiation	Petrochemical

08 Fibers & Industrial Chemicals

A mixed group united by long-latency chronic disease — asbestos and the dioxins are the classic exam anchors here.

Chemical	Appearance	Major Hazard	Chronic Disease	Industries
Asbestos	White-gray fibers	Inhalation	Asbestosis, mesothelioma	Construction
TDI	Colorless-yellow liquid	Asthma	Occupational asthma	Polyurethane
MDI	Brown liquid	Asthma	Occupational asthma	Spray foam
Epoxy Resins	Clear-amber	Skin sensitizer	Allergic dermatitis	Composites
PCBs	Yellow oily liquid	Skin irritation	Cancer/endocrine effects	Transformers
Dioxins	Colorless solids	Highly toxic	Cancer	Incineration
Dibenzofurans	Colorless solids	Highly toxic	Cancer	Combustion
Fluorocarbons	Colorless	Mild ether odor	Cardiac sensitization	Refrigeration

09 Quick Recognition Mnemonics

The substances that show up most often, boiled down to one memory cue each.

Mercury

Mad Hatter — tremor, memory, mood

Lead

Wrist drop + belly pain

Cadmium

Kidneys + bones

Chromium VI

Chrome holes + lung cancer

Beryllium

Granulomatous lung disease

Manganese

Parkinson-like syndrome

Benzene

Bone marrow → leukemia

Methanol

Blindness

Carbon Monoxide

Cherry-red blood (classic)

Hydrogen Sulfide

Rotten eggs, then odor fatigue

Ammonia

Upper airway irritant

Chlorine

Pulmonary edema

Asbestos

Mesothelioma

Important limitations — please read.

This is a recognition aid, not a clinical or regulatory reference. Effects listed are the most commonly cited/tested associations, not a complete toxicological profile. Real-world exposure effects depend on dose, duration, individual susceptibility, and route.

Not a substitute for the SDS or the current ACGIH TLV/BEI booklet. Always verify exposure limits, classifications, and control requirements against the current Safety Data Sheet and the applicable annual ACGIH TLVs & BEIs booklet before applying any of this in practice.

SPEP is not affiliated with BGC/ABIH or BCRSP. This page reflects my own study notes while working through CIH Chapter 4 — it is not official exam content. For the official CIH credential, visit gobgc.org/cih.