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Sulfur dioxide in liquid form tells a story that spans centuries, touching everything from ancient winemaking to the throbbing centers of heavy industry. Early records show the Greeks and Romans burning sulfur to disinfect wine casks, long before anyone bottled the gas or turned it into a chemical mainstay. Demand for a controlled, reliable supply ramped up during the 19th century, fueled by textile processing and the rise of industrial chemistry. Only after refrigeration and pressurization technologies matured did commercial handling of liquid sulfur dioxide become practical. Once engineers figured out how to liquefy and transport SO2 safely, new uses followed. My own first run-in with sulfur dioxide came through academic research: a faint, stinging whiff in a university lab, thick with warnings about gloves and face shields, plus a strong sense that the stuff meant business.
In liquid form, sulfur dioxide looks pretty unremarkable: colorless, mobile, and heavier than water. But anyone who’s handled it knows you’re not dealing with a kitchen chemical. Under pressure or at low temperatures, SO2 condenses and stays liquid. Left on its own at room temperature, it will boil into a choking, suffocating cloud. The commercial product comes in pressurized steel containers with strict labeling, reflecting its volatility and toxic punch. Most of what’s out there is sold at industrial purity, with stringent controls to weed out moisture, halides, and organics. In every sector that leans on it, purity standards come down hard because even a little contamination can ruin a process or create dangerous byproducts.
Sulfur dioxide stands apart for a few basic reasons. It boils at minus 10 degrees Celsius, so you need only modest pressure to keep it liquid at room temperature. The sharp, acrid smell is impossible to ignore, reminding anyone nearby that you don’t want your lungs full of it. Chemically, SO2 behaves as a strong reducing agent, but under the right spark of energy, it will go the other direction and oxidize to sulfur trioxide—just one step from infamous sulfuric acid. Liquid sulfur dioxide can dissolve in water, creating sulfurous acid, a lesser fate than what it can unleash in the wrong hands, but still no joke for skin or mucous membranes. Those physical and chemical basics shape every safety poster, every industrial protocol, and every research breakthrough based on this single compound.
Regulators draw heavy lines around handling, transport, and labeling, and for good reason. Standard packages state chemical identity, net and tare weight, hazard pictograms, and specific instructions about venting and temperature. These aren’t just bureaucratic hurdles: improper labeling has set off more than one evacuation. International rules, such as GHS and DOT requirements, get baked into every container. A worker in shipping or storage doesn’t need reminding: getting this step wrong means a world of hurt, or worse. Industry standards also lay out acceptable concentration ranges for water, acidity, and trace metals. My own work in compliance hammered home how a single mislabel or off-spec batch could shut down a shipment or lead to draconian fines.
Most liquid sulfur dioxide today comes from direct combustion of elemental sulfur in dry air or pure oxygen, followed by cooling, scrubbing, and gas compression. Gone are the days when byproduct streams from metal smelting (often loaded with enough impurities to make your eyes water) supplied the bulk. The actual chemistry is simple: burn sulfur, make SO2 gas, then cool and pressurize. Drying agents strip out water so the product won’t corrode tanks or steel pipes. Downstream reuse of heat and recycling of unreacted sulfur underscore the focus on minimizing waste and staying solvent in a squeezed market. Chemical engineers have shaved years off early production methods—modern plants act more like tuned engines than brute-fire furnaces.
People who spend time in the lab know SO2 doesn’t just sit still. It reacts with numerous compounds: strong bases turn it into sulfites and bisulfites; oxidants push it onwards to sulfur trioxide; certain organics hook onto it for effect, while some metals strip it of electrons. This versatility is a reason you see the compound used in food preservative workflows, water treatment, and syntheses of intermediates for pharma and pesticides. Under pressure and with just the right tweaks, chemists have coaxed new catalysts and reaction pathways, hoping to swap out nastier reagents in existing industrial processes. That’s been true since the mid-20th century, and progress keeps ticking because researchers see the benefit of less toxic byproducts and tighter yields. In my graduate days, I watched a senior scientist wrestle with the stuff—surrounded by vacuum lines and tall flasks—in search of rare ligands. It’s not just textbook chemistry; it’s fueled surprising innovations.
Sulfur dioxide wears a string of alternative names: Sulfurous oxide, sulfur(IV) oxide, and SO2 are the most common. In the world of industrial trade, “liquid sulfur dioxide” flags both purity and phase—distinguishing it from the more familiar, noxious gas. These cross-references surface on regulatory filings, research articles, and procurement documents. The naming conventions sometimes confuse junior chemists, who try to figure out if they’re staring at the same substance as their textbooks describe. Knowing the synonyms matters, though, because cross-border shipments and international safety databases depend on getting the translations right. Missteps in naming have held up imports or caused safety drills in shipping facilities.
Working around liquid sulfur dioxide means taking safety gear seriously: goggles, acid-resistant gloves, ventilation hoods, and personal monitors set to catch leaks or spills. This is not something handled with a shrug or a shortcut. The threshold limit value for vapor is low—breathing too much causes everything from coughing to lung edema. Tank and line design keeps relief valves, rupture disks, and overpressure alarms in the foreground. Training separates those who follow routine from those who improvise in trouble, and you recognize the difference on a walk-through of any facility where the stuff lives. Even the smallest mistake—an unlatched valve, a loose fitting—has triggered overexposures documented in safety bulletins worldwide. Consultants sometimes exaggerate, but here there’s no overstatement: Sulfur dioxide means preparedness, not luck.
Food and beverage producers trust SO2 to stave off spoilage, mostly in dried fruits and wine. Paper mills have long used it in pulping wood because SO2 breaks down fibers without destroying the cellulose needed for strong sheets. In water treatment, the gas neutralizes chlorine and other disinfectants faster than many alternatives. Industrial chemists use it in synthesizing key intermediates and as a solvent for specialized reactions. There’s growing interest in niche applications, from fumigating imported goods to novel electronics etching. From what I’ve seen, the fastest expansion lately links to eco-friendly bleaching agents and efforts to recycle spent chemicals out of wastewater. Waste reduction and sustainability have become talking points, but the direct applications remain anchored by old-school uses.
Science never stops pushing the boundaries laid by the previous generation. Today’s work on sulfur dioxide focuses on high-efficiency capture from flue gases, striving to turn an infamous pollutant into usable stock. Researchers are testing new absorbents, catalysts, and membrane materials in hopes of reducing environmental impacts. In agricultural chemistry, current studies dig into whether SO2 can provide fungicidal action with lower environmental cost than chlorine-based compounds. Physicists and process engineers want more accurate sensors to catch leaks or accidental releases at the earliest possible moment, building in redundancy. My view after years of collaborating with diverse groups: progress depends on breaking down silos between chemists, engineers, and environmental advocates. No one group can tackle both productivity and safety alone.
No sugarcoating this—sulfur dioxide exposure causes harm. Acute symptoms include throat irritation, coughing fits, bronchoconstriction, and sometimes hospitalization for susceptible individuals. Long-term or repeated exposure raises the risk of respiratory disease, especially in children, the elderly, and people with asthma. The medical consensus reflects mountains of toxicological data, with thresholds that get stricter every few years in response to new findings. Animal studies have mapped out the effects of chronic exposure, showing corrosion of airway tissues and disruptions in normal lung function. Real-world incidents—a valve failure here, a spill there—have tragically underscored the need for operational vigilance. New research is probing genetic differences in susceptibility, and epidemiological work guides updated exposure standards. As someone who’s seen the burden on occupational health teams, I know scrutiny isn’t going away.
The future of liquid sulfur dioxide will likely track shifts in environmental regulation, demands for cleaner manufacturing, and breakthroughs in recycling technology. Cleaner processes for capturing sulfur dioxide from smokestacks now matter as much as cost per ton. Regulatory environments shape investment in process upgrades and the willingness of firms to invest in abatement, capture, and reuse schemes. Better monitoring and containment could reduce incidents, saving lives and legal headaches. I see mounting interest in closing the loop—turning what used to be a pollutant into a working reagent, then salvaging and recycling it at end of process lines. The biggest hurdles aren’t always technical but political: balancing economic needs with environmental realities. In research meetings, it’s clear that teamwork across traditional divides is what fuels meaningful advances. Technology should help, but culture shifts in safety, transparency, and risk management will determine if society benefits from the full potential of liquid sulfur dioxide—or just keeps dealing with its dark side.
Most people never think about liquid sulfur dioxide. Yet its value can’t be overstated in several industries. From my work in environmental consulting, I’ve found that it’s more than just a chemical with a complicated name; it’s a real workhorse behind the scenes. You’ll often find liquid sulfur dioxide used in food preservation, industrial bleaching, chemical manufacturing, and even in water treatment. Unlike many chemicals, it offers a mix of versatility and reliability that keeps it in demand, even as new technologies come along.
Wine makers and food processors put liquid sulfur dioxide to work as both a preservative and an antioxidant. If you’ve enjoyed dried apricots or a glass of wine, you’ve probably crossed paths with it—just not directly. In the winery, workers add it to keep bacteria and wild yeast from ruining batches. It also stops browning in dried fruit, locking in color and flavor for longer periods. Regulatory agencies set strict limits to keep these foods safe, but with proper handling, the benefits show up in our pantries and glasses.
Since my father spent much of his career in a paper mill, I got an inside look at how sulfur dioxide shapes industries most folks overlook. The chemical enters the pulp and paper process as a bleaching and anti-chlorination agent. Because it prevents unwanted chemical reactions, mills achieve brighter paper with fewer impurities. Industrial cleaning companies also rely on liquid sulfur dioxide for softening and brightening fibers before turning them into a finished product.
Chemists value liquid sulfur dioxide as a solvent and an intermediate. During the production of dyes, pharmaceuticals, and even refrigerants, sulfur compounds play a key role. Certain pigments and advanced pharmaceuticals depend on sulfur dioxide for crucial reactions. This isn’t just a small-time application—large-scale facilities depend on reliable supply and safe handling practices. Shortages or interruptions can ripple through supply chains, spiking costs for manufacturers and, eventually, for consumers.
In towns with water treatment plants, sulfur dioxide plays a part in keeping tap water clear of excess chlorine. Plant operators use the chemical to “dechlorinate” water as a finishing step before it flows into rivers or the public supply. For me, understanding this process added a layer of respect for municipal workers: keeping water safe isn’t as simple as flipping a switch. Chlorine makes water safe, but too much can cause problems; liquid sulfur dioxide ensures balance without adding more harmful byproducts.
Real experience with sulfur dioxide reminds me how careful the industry must be. It poses dangers if inhaled or released; workers rely on tightly controlled systems, leak detectors, and personal protective equipment. I’ve seen facilities double down on training and emergency drills. Technological advances now offer safer storage and better leak response systems. Still, room exists for improvement through automation, real-time sensors, and transition to lower-risk alternatives where feasible.
Industry continues to work on greener substitutes. Not every application can lose sulfur dioxide overnight, but as research grows, safer and more sustainable methods should gradually reduce dependence without breaking processes already in place.
Liquid sulfur dioxide doesn’t make headlines the way some chemicals do, but anyone who has worked around chemical storage or water treatment plants knows how risky it can be. I learned this truth early, shadowing an experienced plant operator. He made sure I respected the stuff: "Don’t get cocky—one bad move can put you in the ER.” That left an impression.
Sulfur dioxide in its liquid state comes bottled under pressure, and it carries a chilling coldness straight from the tank. The trouble starts with the temperature. Splash some of this on your skin, and you face severe frostbite. I saw a guy pull off his glove once with a bit of snow-white frost on his fingers—no pain at first, but his skin turned black by the end of the week. Folks assume the real risk comes from leaks, when the liquid turns into a suffocating, choking gas. That’s just part of the story.
Walk into a vapor cloud of sulfur dioxide, and the air hits you like pepper spray straight to the lungs. It burns your nose, throat, and eyes. Even a few breaths at low concentrations cause coughing. The real danger comes when concentrations climb higher: lungs fill with fluid, asthma attacks strike, and sometimes people don’t make it out in time. In places where sulfur dioxide gets used for food processing or winemaking, one slip-up leads to evacuations or worse. Medical journals tell story after story—one American Chemical Society study reports lasting lung damage in exposed workers, even with quick medical care.
You won’t smell it before it’s too late. Sulfur dioxide’s sharp odor lingers right above the threshold where it causes harm. High enough, and your nose stops working entirely, turning off the body’s alarm system. That’s a trickier problem than most people expect. Relying only on your nose or eyes means you can’t react quickly enough to dangerous leaks.
Nobody in the business takes shortcuts with sulfur dioxide. Full-face respirators, chemical suits, and gloves at every turn. Plant safety rules demand alarms, emergency showers, and ample ventilation. OSHA calls for exposure monitoring and strict storage protocols. These measures don’t just serve red tape; they save lives. A single missed step ends with real harm. During my time at a small municipal water plant, even seasoned staff double-checked valves, checked for leaks with wands or sensor badges, and never opened storage tanks alone.
Accidents still happen. Leaks, improper storage, and faulty pumps have sent emergency crews scrambling. In some cities, community notification systems now trigger if storage tanks get breached. Chemical spill drills, better leak detection, and the switch to less hazardous alternatives, like sodium bisulfite, help cut the risk. Small operators—sometimes with thin budgets—push for automatic shut-off valves and remote monitoring, knowing how quickly things can turn dangerous.
For all the challenges, safer practices keep getting better. Companies invest in better training and push to swap out sulfur dioxide where possible. Plant managers, even in tough economic times, push for upgrades. Regulators encourage new tech—electronic sensors, stronger tanks, better process controls. Community groups work with plants to help people understand the risks and prepare for emergencies, building trust rather than just raising alarms.
Experience taught me respect for sulfur dioxide. Handling this chemical safely calls for focus, protective gear, and a willingness to admit when you don’t know something. Lives depend on each step. No cutting corners. That’s the real lesson behind the danger.
Liquid sulfur dioxide gives off a sharp odor and reacts pretty aggressively with water. Spend any time around chemical plants, and you’ll hear old-timers talk about stories of pipes icing up or valves freezing shut because of mishandled SO2. This stuff brings real risks if folks get lax with storage or processes.
Storing liquid sulfur dioxide isn’t just about following rules on paper. At ambient conditions, it turns from liquid to vapor in no time, and the vapor will try to escape any way it can. Leaks won’t hide—the sharp, choking odor hits fast. Breathing in even low concentrations causes coughing, throat tightness, or more severe lung injury. Direct contact with the liquid means frostbite or chemical burns. Hazards stack up quickly.
Facilities that keep SO2 use tightly sealed steel tanks, built to handle pressure swings between about 2 and 5 bar, since the boiling point sits at –10°C at atmospheric pressure. Every valve, flange, and fitting needs careful selection—old, rusted-out hardware doesn't cut it. Many places use carbon steel, though the industry also moves toward stainless alloys in tough climates or where acids splash around.
When temperatures climb, vapor pressure in tanks jumps too. Insulation helps, but so do sunshades and location in the coolest patch of the yard. I’ve watched teams wrap tanks with heat-reflecting blankets to squeeze extra safety out of marginal setups. Nobody trusts a tank left baking in the middle of July.
Transfer lines pose just as much risk. Keeping them short, tight, and above ground where possible means you can inspect everything easily. Drip pans underneath and emergency shutoff valves near transfer points let operators stop a spill before it turns ugly. You don’t want a situation where a small hose leak becomes a full-scale evacuation.
Working with sulfur dioxide never becomes routine. New staff learn the hard way that half-masks won’t protect against real releases—a full-face respirator or supplied air works best for anyone on the front line. Suits lined with PVC or other chemical resistance help with splashes, though eyesight and airways remain the top concerns.
Emergency showers and eyewash stations sit close by, checked every shift. Rescue plans grow specific—everyone drills for both small leaks and high-volume releases. Fast notification to local emergency responders and neighbors builds trust, even if you hope those messages stay unused.
Routine inspections show their value over and over. Gaskets harden with time, welds can stress, and telltale white stains hint at slow leaks—these little clues allow teams to catch problems before bigger consequences follow. Solid documentation, from site plans to tank ratings to valve history, helps workers move quickly when things get tense.
Leak detection, whether by simple soap solution or infrared sensors, provides early warning. Installing double-walled pipes and adding secondary containment keeps small errors from escalating. Better ventilation in storage sheds cuts buildup of dangerous concentrations during hot spells. Moving toward automation for loading and unloading shrinks human exposure time.
Storage and handling of liquid sulfur dioxide draw on tough lessons learned from accidents and near-misses. Plants that take shortcuts find themselves in the news for all the wrong reasons. Sticking with best practice, sharing lessons between sites, and using technology to monitor risks pays off both for worker health and public safety.
Sulfur dioxide in its liquid form means serious business. It stays cold, under pressure, ready to boil off if something goes wrong. I’ve seen the caution around these shipments firsthand working plant-side—nobody jokes about a tank truck full of this stuff. The chemical burns your lungs, chokes up the throat, and leaks create chaos before first responders have time to react. Sulfur dioxide keeps food fresh and makes paper brighter, but moving it to those factories takes focus on safety above all else.
Truckers and rail operators favor pressurized, insulated tanks made from steel. Dense, double-walled vessels prevent the liquid from flashing into gas when outside air sneaks in. Railcars show up with robust relief valves and strong couplings, all designed to hold tight under pressure swings and jolts from rail yards. The same goes for highway tank trucks—drain valves, tightly-sealed manways, and special hoses make every connection matter.
I recall a friend who drove a hazmat route mentioning the constant inspections—look for frost, check every gauge twice, smell the air near every line before touching a handwheel. Sulfur dioxide brings government eyes, too. Nobody wants a gas cloud drifting down Main Street just because someone cut corners on a fitting.
Production plants transfer the cold liquid into these sealed tanks at controlled terminals. The process looks like a ballet of hoses and workers in heavy gloves and goggles. Supervision turns fierce, alarms ready to blare if a valve sticks or a pump hesitates. Drivers take direct routes to minimize stops, avoiding crowded streets or tight neighborhoods where an accident causes real trouble.
Once delivered, industries use closed-loop systems with stainless pipes. Workers connect transfer lines, vent off excess pressure, and start pumps only after a dozen checks. Nobody at these transfer docks forgets the stories of leaks in old rail yards. A lesson I picked up early from a safety manager: treat every connection as if it hides a risk—because it often does.
Special certification, ongoing education, and practice drills make a difference. I remember mock spill exercises—suits zipped up, sirens wailing, every second counting. A lot of problems never happen because workers spot them in training. Local fire teams tour the rail yards and plant docks, learning layouts and shutdown buttons long before they ever handle an emergency.
Technology improves tracking and monitoring. GPS, digital pressure sensors, and remote valve checks alert operators if conditions change. Companies invest in newer tank fleets and push for stronger oversight. Too many past incidents forced these advances—none forgotten by the crews who handle this chemical today.
Investing in robust equipment, real training, and regular audits pulls the risk down. Every time I pass one of those specialized tankers rolling down the highway, I picture the layers of care built into moving that load safely to its destination.
Food firms work with liquid sulfur dioxide for more than just keeping fruit fresh. Winemakers use it as a preservative during fermentation, guarding against unwanted bacteria and wild yeasts that would ruin a batch. Dried fruit producers reach for it because it keeps apricots and golden raisins from turning brown and losing shelf appeal. Packagers in fruit canning plants also rely on sulfur dioxide to preserve color and flavor, especially in peaches and cherries. If you’ve ever bitten into a bright, cheery dried apricot, you’ve probably tasted a bit of chemistry at work.
Folks who work in pulp and paper operations know that turning wood chips into bright white paper isn’t just about chopping and pressing. Bleaching wood pulp involves cooking it with several chemicals, and sulfur dioxide plays a starring role. Under steam and pressure, it helps break down lignin, a tough compound giving trees their structure. Without this process, newspapers would look much duller, and glossy magazines would lose their sparkle. The shift to liquid sulfur dioxide, instead of gas or other agents, lets producers manage the process with more precision.
The chemical sector banks on sulfur dioxide for a roster of reasons. Intermediate compounds like sodium hydrosulfite—used in textile dyeing and printing—begin with a base of liquid sulfur dioxide. Leather tanners use it, too, to keep hides from spoiling before the slow work of turning them into boots or jackets. The pharmaceutical world taps sulfur dioxide to purify or modify certain active ingredients. Chemical makers prefer the liquid form for easier handling and dosing than the unwieldy gas.
City water managers understand chlorine can’t just be dumped into pipes with wild abandon. After doing its job disinfecting water, leftover chlorine must be removed before reaching homes. Sulfur dioxide, when injected at the right moment, neutralizes excessive chlorine fast, no fuss. This step keeps networks safe and helps avoid the taste and odor folks complain about. Industrial plants running their own wastewater systems have picked up on this trick, as strict discharge rules get tighter every year.
Workers in mining outfits often use sulfur dioxide to separate precious metals—think copper or molybdenum—from unwanted impurities. In flotation and leaching, sulfur dioxide adjusts pH levels and controls oxidation. Years ago, plants pumped out waste without much thought for the land or streams nearby; today, many sites recycle sulfur dioxide on-site to keep environmental harm in check and comply with tough modern rules.
Every industry has safety concerns, and those handling sulfur dioxide know this as well as anyone. Accidents involving leaks can threaten workers and nearby communities, making storage and training a serious business. New technologies offer leak detectors, scrubbers, and protective gear, but the main safety net still comes down to regular practice and clear rules on the ground. Sourcing matters, too: companies try to trace their sulfur supply so mines or refineries meet rising environmental standards.
As more markets turn toward sustainability, industries using sulfur dioxide face new challenges. Pressure mounts for food processors to find gentler ways to preserve fruits. Paper makers experiment with enzyme alternatives. Water plants pilot ozone and ultraviolet treatments. The right approach isn’t always clear. For now, sulfur dioxide remains a workhorse chemical for those who know its value and respect its risks. Facing stricter controls and greener demands, many of these sectors will likely adapt without dropping this old standby overnight.
| Names | |
| Preferred IUPAC name | sulfur dioxide |
| Other names |
Sulfur dioxide solution SO2 solution Sulphur dioxide liquid Liquefied sulfur dioxide |
| Pronunciation | /ˈlɪkwɪd ˌsʌlfə daɪˈɒksaɪd/ |
| Identifiers | |
| CAS Number | 7446-09-5 |
| Beilstein Reference | 1200919 |
| ChEBI | CHEBI:17359 |
| ChEMBL | CHEMBL1358 |
| ChemSpider | 18762 |
| DrugBank | DB11582 |
| ECHA InfoCard | 100.028.609 |
| EC Number | 231-195-2 |
| Gmelin Reference | Gmelin Reference: **1312** |
| KEGG | C01441 |
| MeSH | D013438 |
| PubChem CID | 947 |
| RTECS number | WS4550000 |
| UNII | UNII: AG83G77IXK |
| UN number | UN1079 |
| CompTox Dashboard (EPA) | C274872 |
| Properties | |
| Chemical formula | SO2 |
| Molar mass | 64.07 g/mol |
| Appearance | Colorless liquefied gas with a pungent, suffocating odor |
| Odor | Pungent |
| Density | 1.43 g/cm³ |
| Solubility in water | soluble |
| log P | -0.38 |
| Vapor pressure | 3,000 mmHg (20°C) |
| Acidity (pKa) | 1.81 |
| Basicity (pKb) | 8.38 |
| Magnetic susceptibility (χ) | −34.6×10⁻⁶ |
| Refractive index (nD) | 1.335 |
| Viscosity | 0.41 cP (at 0°C) |
| Dipole moment | 1.63 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 248.2 J/(mol·K) |
| Std enthalpy of formation (ΔfH⦵298) | -296.8 kJ·mol⁻¹ |
| Std enthalpy of combustion (ΔcH⦵298) | -296.8 kJ mol⁻¹ |
| Pharmacology | |
| ATC code | J01XX01 |
| Hazards | |
| Main hazards | Toxic by inhalation, causes severe burns, reacts violently with water, corrosive to eyes and skin, may cause respiratory irritation. |
| GHS labelling | GHS02, GHS04, GHS05, GHS06 |
| Pictograms | GHS02,GHS04,GHS06 |
| Signal word | Danger |
| Hazard statements | H314: Causes severe skin burns and eye damage. H331: Toxic if inhaled. H335: May cause respiratory irritation. |
| Precautionary statements | P210, P220, P221, P260, P261, P271, P280, P284, P302+P352, P304+P340, P305+P351+P338, P308+P313, P310, P320, P340, P403, P405, P501 |
| NFPA 704 (fire diamond) | 3 0 0 Acid |
| Flash point | -54°C |
| Autoignition temperature | 430°C (806°F) |
| Explosive limits | Explosive limits: 7.0% - 18.0% |
| Lethal dose or concentration | LD₅₀ (oral, rat): 2520 mg/m³ (4 h) |
| LD50 (median dose) | 1,000 mg/kg (rat, oral) |
| NIOSH | RS6400000 |
| PEL (Permissible) | 5 ppm |
| REL (Recommended) | 0.2 ppm |
| IDLH (Immediate danger) | 100 ppm |
| Related compounds | |
| Related compounds |
Sulfurous acid Sodium sulfite Sulfur dioxide Sodium thiosulfate |
