SELENIUM DIOXIDE

A white or creamy-white volatile lustrous crystal or crystalline powder with a pungent sour smell. Melting point 340 deg C. Density 3.954 g / cm3. Toxic by ingestion and inhalation.

• Strong Oxidizing Agent

In presence of water will corrode most metals (USCG, 1999). Readily soluble in water forming selenious (selenous) acid.

Special Hazards of Combustion Products: Sublimes and forms toxic vapors when heated in fire. (USCG, 1999)

Absorption of selenium may be demonstrated by presence of the element in the urine and by a garlic-like odor of the breath. Inhalation of dust can cause bronchial spasms, symptoms of asphyxiation, and pneumonitis. Acute symptoms of ingestion include sternal pain, cough, nausea, pallor, coated tongue, gastrointestinal disorders, nervousness, and conjunctivitis. Contact with eyes causes irritation. (USCG, 1999)

Inorganic oxidizing agents, such as SELENIUM DIOXIDE, react with reducing agents to generate heat and products that may be flammable, combustible, or otherwise reactive. SELENIUM DIOXIDE reacts with water, particularly hot water, to give selenious (selenous) acid, a weak acid that is corrosive. Stable to light and heat. Rapidly absorbs dry hydrogen fluoride, hydrogen chloride, hydrogen bromide to form the corresponding selenium oxohalide. A good oxidizing agent. Reacts oxidatively with ammonia to form dinitrogen gas and selenium [Merck]. Oxidizes many organic substances.

• Oxidizing Agents, Strong

Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below.

• Cellulose-Based Absorbents
• Expanded Polymeric Absorbents

Excerpt from 151 [Substances - Toxic (Non-Combustible)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.

FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2020)

Excerpt from 151 [Substances - Toxic (Non-Combustible)]:

SMALL FIRE: Dry chemical, CO2 or water spray.

LARGE FIRE: Water spray, fog or regular foam. If it can be done safely, move undamaged containers away from the area around the fire. Dike runoff from fire control for later disposal. Avoid aiming straight or solid streams directly onto the product.

FIRE INVOLVING TANKS OR CAR/TRAILER LOADS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Do not get water inside containers. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2020)

Excerpt from 151 [Substances - Toxic (Non-Combustible)]:

Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. Cover with plastic sheet to prevent spreading. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS. (ERG, 2020)

This compound is highly toxic if inhaled or ingested. Dust mask; rubber gloves; protective clothing (USCG, 1999)

No information available.

Consult physician after all exposures to this compound.

INHALATION: remove victim to fresh air; give oxygen if needed.

INGESTION: induce vomiting; follow with gastric lavage and saline cathartics.

EYES: flush immediately and thoroughly with water.

SKIN: flush with water. (USCG, 1999)

• SELENIOUS ANHYDRIDE
• SELENIUM DIOXIDE
• SELENIUM OXIDE