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Name: Celite 545
Chemical Description: Diatomaceous Earth, mainly amorphous silica
Appearance: Fine white to cream-colored powder
Main Use: Often used as a filter aid in laboratories and industries, sometimes found in pool filtration or beer clarification
Hazard Classification: Celite 545 does not ignite by itself and does not explode. Main concern comes from fine dust, which can cause irritation, especially in lungs, eyes, or on the skin with repeated or heavy contact. The dust’s crystalline silica content—which can vary by batch and source—has drawn warnings from occupational safety agencies because long-term inhalation of respirable crystalline silica is linked with silicosis and increased lung cancer risk.
Substance: Silica, amorphous (80-95 percent)
Possible additional content: Small quantities of crystalline silica (quartz, cristobalite)
Impurities of note: Aluminum oxide, iron oxide—usually present at lower levels, but can add to dust burden if mishandled
Inhalation: Move the person to fresh air, away from the dusty environment. Coughing or throat discomfort rarely lasts for more than a few minutes, but persistent coughing is a signal to seek medical help.
Eye Contact: Rinse eyes gently with clean water, without rubbing. Use an eyewash station if available. The grit can be abrasive, so continuing irritation means a quick trip to a healthcare provider can keep things from getting worse.
Skin Contact: Brush powder off skin, then wash with mild soap and water. If dryness or irritation appears, a standard skin moisturizer helps.
Ingestion: Because this is technically an inert mineral, Celite 545 rarely causes immediate trouble if swallowed in tiny amounts, but drinking water to aid passage is still a good idea. For larger ingestions or if any symptoms develop, direct medical advice is best.
Flammability: Celite 545 won't catch fire or support a blaze.
Fire Hazards: It can scatter fine dust around a site, and if other stuff catches fire, the reduced visibility from airborne powder can complicate evacuation or rescue.
Recommended Media: Usual firefighting methods—water, foam, CO2, dry chemical—are all safe around Celite 545.
Protective Equipment: Standard protective gear includes respiratory protection to avoid dust clouds kicked up during firefighting.
Personal Precautions: Limit entry to the affected area until dust settles. Dust masks or respirators go a long way, especially in confined or poorly-ventilated spots.
Environmental Precautions: Avoid washing large amounts into drains, since the powder can thicken and clog pipes.
Clean-Up Methods: Use damp sweeping or vacuuming, not dry brooming or compressed air. Wet methods keep the powder out of the air and away from lungs.
Handling: Handle the powder with care so as not to stir up clouds of dust. Good local exhaust ventilation helps keep airborne concentrations down.
Storage: Store in sealed, well-labeled bags or containers, away from humidity and incompatible chemicals like strong alkalis or hydrofluoric acid. Avoid letting the material get wet, as this can turn it into a slippery paste and complicate disposal.
Engineering Controls: Use local exhaust or general room ventilation during weighing and mixing. When dumping or transferring Celite 545, dust-proof hoods or enclosures matter.
Personal Protective Equipment (PPE): NIOSH-approved dust masks or respirators for heavy exposure, safety glasses or goggles, gloves for prolonged handling, protective clothing for long exposure or high-dust settings.
Occupational Limits: Follow guidance from OSHA, ACGIH, or local bodies for respirable silica. For amorphous silica, workplace limits are more lenient, but the risk increases with fine crystalline fractions.
Physical State: Free-flowing powder
Color: Off-white to pale gray
Odor: Odorless
Melting Point: About 1,700°C (for silica)
Solubility: Insoluble in water, non-reactive with most common chemicals
Other: Lightweight feel, can quickly become airborne in a draft or with vigorous handling
Stability: Stable under reasonable conditions. It won’t degrade in normal environments.
Reactivity: Strong acids like hydrofluoric acid dissolve silica, releasing toxic byproducts. Strong alkalis can cause slow breakdown, but not with casual contact.
Hazardous Decomposition: No dangerous gases or toxins given off below normal industrial heating.
Acute Effects: Gritty, dusty material can irritate eyes, lungs, and skin.
Chronic Effects: Fine particulate crystalline silica leads to silicosis after repeated exposure, which is a progressive, untreatable lung disease. Amorphous silica, the major fraction in Celite 545, is considered a “nuisance dust” by OSHA, but presence of crystalline fractions means chronic exposure brings risk.
Cancer Risk: IARC classifies amorphous silica as Group 3 (not classifiable), but certain crystalline forms shift it into Group 1 (carcinogenic to humans), so it’s best to play it safe.
Persistence and Degradability: Natural mineral, persists unchanged in soil or water. Won’t break down easily.
Mobility: Fine particles can be carried by wind or water, but pose low toxicity to wildlife. Some species may experience gut abrasion if large amounts are ingested.
Bioaccumulation: No evidence for bioaccumulation in animals or plants, since silica passes through systems unchanged.
Waste Disposal: Dispose of as non-hazardous industrial waste, unless local tests indicate higher crystalline silica content. Landfills usually take Celite 545, so long as it’s not contaminated with hazardous materials.
Avoid: Dumping large amounts into the environment, sewers, or water supplies, since this may cause blockages or temporary turbidity problems. Damp down any waste to prevent dust, then seal in heavy-duty bags before collection.
UN Number: Not regulated by most transport codes as a hazardous good.
Shipping Notes: Ship in strong, sealed bags or drums to avoid leaks during transit. Avoid loading with chemicals incompatible with silica or materials that could turn the powder into sludge.
Workplace Regulations: OSHA and similar bodies set exposure limits for amorphous silica (typically 6 mg/m3 time-weighted average for dust) and much stricter limits for respirable crystalline silica (about 0.05 mg/m3).
Labeling: Labeling laws focus on potential respiratory hazards, especially for users or work crews. Dust warnings and recommendations for PPE are standard wherever fine powders are involved, and Celite 545 is no exception.
