Chromic acid (chromium trioxide) in the yard and garden
Extreme risk for your yardChromic acid presents an extreme risk to human adults — it is both a confirmed lung carcinogen (IARC Group 1 Cr(VI)) and an acutely corrosive, oxidizing hazard. Occupational exposure in hard chrome electroplating, chromate conversion coating, and anodizing requires the most stringent controls: enclosed/ventilated plating baths with local exhaust ventilation, real-time hexavalent chromium air monitoring, OSHA Cr(VI) standard compliance (PEL 5 μg/m³), supplied-air respirators for maintenance tasks, and biological monitoring (urine Cr). Long-term Cr(VI) exposure causes lung cancer, nasal septum ulceration and perforation, chrome holes (skin ulcers from Cr(VI) contact), and occupational asthma. REACH Authorisation requirements apply in the EU. Not for use without documented authorization and engineering controls.
What is chromic acid (chromium trioxide)?
The IUPAC name is trioxochromium.
Also known as: trioxochromium, Chromium trioxide, Chromium(VI) oxide, CrO3.
- IUPAC name
- trioxochromium
- CAS number
- 1333-82-0
- Molecular formula
- CrO3
- Molecular weight
- 99.994 g/mol
- SMILES
- O=[Cr](=O)=O
- PubChem CID
- 14915
Risk for people, pets,
Extreme riskChromic acid presents an extreme risk to human adults — it is both a confirmed lung carcinogen (IARC Group 1 Cr(VI)) and an acutely corrosive, oxidizing hazard. Occupational exposure in hard chrome electroplating, chromate conversion coating, and anodizing requires the most stringent controls: enclosed/ventilated plating baths with local exhaust ventilation, real-time hexavalent chromium air monitoring, OSHA Cr(VI) standard compliance (PEL 5 μg/m³), supplied-air respirators for maintenance tasks, and biological monitoring (urine Cr). Long-term Cr(VI) exposure causes lung cancer, nasal septum ulceration and perforation, chrome holes (skin ulcers from Cr(VI) contact), and occupational asthma. REACH Authorisation requirements apply in the EU. Not for use without documented authorization and engineering controls.
Regulatory consensus
4 regulatory and scientific bodies have classified Chromic acid (chromium trioxide). The classifications differ — that's the data.
| Agency | Year | Classification | Notes |
|---|---|---|---|
| IARC | 2012 | Group 1 — Chromium(VI) compounds are carcinogenic to humans (IARC Monograph Volume 49, 1990; Volume 100C, 2012); chromic acid (CrO3) is one of the primary Cr(VI) sources evaluated; lung cancer causation in chromate production, chrome plating, and pigment manufacturing workers is established | |
| EPA CTX / NTP RoC | — | Known Human Carcinogen | |
| EPA CTX / Genetox | — | Genotoxicity: positive (Ames: positive, 7 positive / 0 negative reports) | |
| EPA CTX / Genetox | — | Genotoxicity: positive (Ames: positive, 7 positive / 0 negative reports) |
Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.
Where your yard encounter chromic acid (chromium trioxide)
- Contaminated Water — Mining site runoff, Industrial discharge areas, Drinking water from old infrastructure
- Soil Contamination — Industrial sites, Smelter areas, Battery recycling facilities
- Food Chain — Fish from contaminated waters, Shellfish from polluted areas, Crops grown in contaminated soil
Safer alternatives
Lower-risk approaches that achieve a similar outcome to Chromic acid (chromium trioxide):
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Enzyme or biocatalysts where applicable
Trade-offs: Temperature/pH sensitivity. Higher cost for some applications.Relative cost: 2-5×
Frequently asked questions
Is chromic acid (chromium trioxide) safe for your yard?
Chromic acid presents an extreme risk to human adults — it is both a confirmed lung carcinogen (IARC Group 1 Cr(VI)) and an acutely corrosive, oxidizing hazard. Occupational exposure in hard chrome electroplating, chromate conversion coating, and anodizing requires the most stringent controls: enclosed/ventilated plating baths with local exhaust ventilation, real-time hexavalent chromium air monitoring, OSHA Cr(VI) standard compliance (PEL 5 μg/m³), supplied-air respirators for maintenance tasks, and biological monitoring (urine Cr). Long-term Cr(VI) exposure causes lung cancer, nasal septum ulceration and perforation, chrome holes (skin ulcers from Cr(VI) contact), and occupational asthma. REACH Authorisation requirements apply in the EU. Not for use without documented authorization and engineering controls.
What products contain chromic acid (chromium trioxide)?
Chromic acid (chromium trioxide) appears in: Mining site runoff (Contaminated water); Industrial discharge areas (Contaminated water); Industrial sites (Soil contamination); Smelter areas (Soil contamination); Fish from contaminated waters (Food chain).
Why do regulators disagree about chromic acid (chromium trioxide)?
Chromic acid (chromium trioxide) has been classified by 4 agencies including IARC, EPA CTX / NTP RoC, EPA CTX / Genetox, EPA CTX / Genetox, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.
See Chromic acid (chromium trioxide) in the outdoor app
Look up products containing chromic acid (chromium trioxide), compare to alternatives, and explore the full data record.
Open in outdoor View raw API dataSources (1)
- IARC Group 1 Chromium VI Compounds Vol 49 1990 Vol 100C 2012; Chromic Acid CrO3 Hard Chrome Electroplating Lung Cancer; Nasal Septum Perforation Chrome Holes; Cr-DNA Adducts ROS Cr(V) Reductive Activation; EU CLP Carc 1A H350i SVHC REACH Authorisation List; OSHA Cr(VI) Standard 5 μg/m3 2006; Hinkley California Erin Brockovich Groundwater; EU WFD Priority Substance; Aquatic Acute 1 H400 (2012) — regulatory
Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →