Cresol Red didn’t arrive overnight. Its story goes back to early dye chemistry, tracing roots in the late 1800s, connecting with titration dyes and pH indicators that shaped lab routines for more than a century. Chemists like Arthur Hantzsch played their part, hunting for easier ways to measure acidity and making lab work less guesswork, more certainty. Dyes like Cresol Red grew popular as the practical needs of everyday laboratory science shifted deeper into precision. I remember hearing from old mentors how pH test strips and indicators transformed classroom teaching into hands-on experience, not dry theory. The rise in popularity reflected real shifts in what scientists and students needed — dependable, simple, clear results. Manufacturers recognized demand from schools, clinics, and water works. As biotech boomed through the seventies and eighties, and as PCR became essential in molecular biology, the demand for reliable dyes only grew. Cresol Red’s chemistry lent itself to easy synthesis and accuracy, which never went out of fashion.
Cresol Red stands out among the pH indicators and DNA loading dyes that show up in a cabinet or chemical order. Sold as a solid powder, it dissolves quickly in water or alcohol, giving a vivid transition from yellow to red to purple. That color change isn’t just for show. In lab routines, it lets researchers judge pH shifts by eye, and during gel electrophoresis, helps track DNA movement without having to stop and guess. Anyone who’s run agarose gels for DNA or RNA probably recognizes Cresol Red in the mix. Companies like Sigma-Aldrich, Thermo Fisher, and others keep it on tap because its reliability built trust. Students spot it in classroom kits. Research operations buy in bulk for large sequencing projects. In the clinics, the dye sneaks behind the curtain as a safe visual clue, not exposing test results to ambiguous interpretation.
Cresol Red’s structure combines three cyclic rings with sulfonate and phenol functional groups. Solid at room temperature, it looks like a brownish or reddish powder, almost nondescript, but once mixed in solution, its distinct chromatic changes stand out — yellow below pH 7, red above 8.8, and purple higher still. Water solubility is decent, though it prefers ethanol when you need higher concentration stocks. Melting point falls around 218°C, which means it handles moderate heat without decomposing. Its molecular weight of around 382 g/mol gives a fine balance—enough heft for stable solutions, light enough to dissolve cleanly. That stability puts it ahead of dyes that degrade under strong light or temperature changes, letting it sit on a shelf or bench for weeks, ready to go. I’ve spilled it in more than one classroom and can tell you: clean-up is easy, and its chemical behavior strengthens its role as a low-maintenance staple.
Suppliers package Cresol Red with strict labeling guidelines following global standards like GHS. You’ll see batch number, purity (usually over 90%), and expiration date. Some bottles carry certificate of analysis details, which might seem bureaucratic, but ensures traceability that research audits demand. Labels flag safe handling instructions and storage (keep in a sealed container, out of direct sunlight). Every commercial bottle includes hazard pictograms — avoiding confusion and cutting risk in a busy teaching or industrial setting. Labels highlight solubility information and instructions for solution preparation, guiding users straight to proper concentrations whether they mix tiny 0.1% stocks for gels or larger volumes for bulk work. Shelf life usually stretches to several years if kept cool and dry. Every time I check expiry, I’m reminded that a little oversight in storage cuts down accidental mistakes and keeps experiments reproducible, especially in crowded shared labs. Technical sheets push users to verify buffer compatibility and to avoid mixing with reactive chemicals that could break down the indicator or cloud results.
Direct synthesis of Cresol Red relies on coupling p-sulfonic acid benzene with o-cresol and formaldehyde using condensation, then further sulfonation steps. The basic procedure keeps steps straightforward for large-scale manufacturers. Lab-grade stocks start by dissolving Cresol Red powder in distilled water or buffer, usually at concentrations between 0.05% and 0.1% w/v. For gel electrophoresis, I’ve found that heating the solution helps speed up dissolution, avoiding chunks that throw off loading lanes. Filtering through a 0.22-micron membrane strips out undissolved particles, giving a clear red solution that lasts for weeks in the fridge. For PCR or isothermal reactions, Cresol Red mixes into premade buffer kits, with concentrations adjusted so it doesn’t interfere with polymerases. Practical prep steps echo a bigger point: clear recipes for mixing, filtering, and storing help prevent human error, making scientific routine smoother and safer.
Cresol Red’s main chemical trick is changing color as its structure shifts under acidic or basic conditions, thanks to movement of protons in the phenol group and changes in conjugation across its rings. Labs don’t usually need complex modifications because its core function works out-of-the-box. Advanced research sometimes tacks side chains to the aromatic rings — introducing tags or linkers to fix Cresol Red to resins or polymers for high-throughput assays. A few specialty suppliers offer phosphorylated or alkylated versions for applications that demand enhanced stability or altered solubility. Its basic skeleton resists most mild oxidants and stands up to regular buffer mixes. Strong acids or bases break it down, but under normal lab use, its resilience means fewer headaches from random degradation. From experience, sticking to standard phosphate buffers at near-neutral pH gives the longest shelf life in routine DNA work.
Cresol Red goes by more than one name, which sometimes causes confusion in online shopping or literature searches. Literature will reference o-Cresolsulfonphthalein, or C.I. Acid Red 77. Product listings might add variations: 3,3-Bis(4-hydroxy-2-methylphenyl)-2,1-benzoxathiol-1,1-dioxide or simply “sulfonphthalein dye.” Ringing up a chemical supplier, I double-check catalog numbers compared to synonyms, sidestepping mix-ups with similar-sounding products like Phenol Red or Bromocresol Green. This matters in fast-paced or multilingual settings where translation can miss nuances. Teachers and lab techs, especially, benefit when suppliers list other names in product catalogs and on certificates of analysis, cutting down the chance of someone grabbing the wrong bottle off the shelf.
Cresol Red’s low toxicity gives some flexibility, but safe handling isn’t optional. Material Safety Data Sheets put it in the “handled with care” category, flagging eye, skin, and inhalation risks. In a spill, a dust mask and gloves prevent irritation — direct experience showed me that even simple contact can cause mild itching or sneezing. Labs standardize PPE: goggles, gloves, and closed storage. Waste disposal follows municipal rules — water-soluble, small-scale amounts go to drain with copious water, but bulk quantities need chemical waste channels. Labs train staff to treat all dyes as potential hazards, backing up the rules with signage and quick-access wash stations. Proper training keeps labs safe and ready for inspection, which satisfies regulatory bodies and ensures new hires don’t face unnecessary risk. Transport rules stack up stricter for larger quantities or across borders, making product registration and MSDS paperwork non-negotiable.
Educational work, DNA gel loading, pH titrations, and PCR kit preparation all benefit from Cresol Red’s clear color change and straightforward handling. Its non-reactive nature means it won’t sabotage enzymes or bind DNA, which keeps downstream analysis honest. In water quality labs, Cresol Red offers quick field checks without expensive meters — just a drop in a test tube to get a readable shift. Clinical diagnostics like urinalysis or acid-base panels rely on color indicators, and although not as universal as Phenol Red, Cresol Red holds its niche where sharper color boundaries matter. Environmental researchers use it in buffer prep to sort acidic from basic soils during fieldwork. I recall practical experiences in classroom labs, where its distinct range made it easy to teach fundamentals of acid-base chemistry. Across boardrooms, from product development to customer tech support, a reliable visual indicator simplifies SOPs and brings confidence to routine protocols.
R&D isn’t static; users keep searching for more robust indicators that handle wider pH ranges or resist photobleaching. Biotech companies tune Cresol Red formulations, blending it into ready-to-use dye mixes or customizing buffer systems. In synthetic biology, researchers test new variants, aiming to tweak solubility or build in fluorescence for better sensitivity. Collaborative projects invite feedback from academic and clinical end-users, who report bugs or every unexpected reaction, spurring upgrades in both commercial and research contexts. Academic publications keep pushing tweaks, designing analogs or modifying groups to broaden the utility in advanced analytical methods. Personal exchanges with research staff highlighted that scalable, easy-to-make dyes win out, especially where budgets run tight and supply chain disruptions force last-minute substitutions. R&D also branches into automation, where dyes like Cresol Red provide simple color cues for robotics and sensor arrays in workflows that demand real-time quality control.
Risk assessment teams start with animal toxicology and move to environmental fate. Cresol Red turns up much lower toxicity than similar aromatic compounds. Oral and inhalation studies in rodents set clear safety thresholds, and most human exposure in controlled settings causes no lasting harm beyond mild irritation — precautions focus on preventing chronic exposure rather than the rare acute incident. Environmental studies track breakdown and find minimal bioaccumulation, with rapid degradation in wastewater. Still, low-level aquatic toxicity exists, so large-scale users receive strict guidance for disposal and cleanup. University biosafety committees audit protocols and monitor downstream effluent, encouraging green chemistry principles and slow replacement of dyes with even lower toxicity. It pays to check for new data, because regulatory bodies like the EPA or ECHA periodically adjust usage recommendations based on updated hazard studies. If Cresol Red raised bigger toxicity flags, manufacturers would move faster toward greener replacements, but for now, its safety in routine use stands supported by decades of low-incident research.
Users look ahead for dyes that work harder, last longer, and stay greener. Researchers pursue modifications that attach reporter molecules or add photostability, hoping to stretch beyond traditional color changes and into multipurpose sensors. Green chemistry advocates push for water-based synthesis and recycled raw materials. Automation engineers want dyes like Cresol Red to play larger roles in on-the-fly diagnostics, especially where color cues drive software-controlled pipetting and sorting. I hear from colleagues that regulatory pressures nudge labs to trim waste and choose lower-risk chemicals; Cresol Red’s modest environmental footprint and proven record help, but market forces keep pressure on suppliers to innovate. In classrooms, digital pH meters might crowd out older indicators someday, but simple, visual systems remain vital in hands-on learning and resource-limited settings. Advances in combinatorial chemistry and high-throughput screening mean future indicator dyes will likely evolve, yet the need for straightforward, reliable visual tools ensures that the lessons and routines built on Cresol Red hold relevance for years to come.
Cresol Red usually finds its way onto lab benches covered with pipettes, small bottles, and stacks of sticky notes. You don’t hear about it outside of specific classrooms and research settings, but once you’ve used it, you remember it. It’s a dye—a pH indicator, to be specific. In the world of molecular biology, Cresol Red does the sort of job most people forget exists: it helps scientists know if a reaction is working, if a gel is loading correctly, and if the conditions in their tubes are just right.
Don’t let the deep red color fool you. In PCR (Polymerase Chain Reaction), Cresol Red helps track how much sample goes into the gel. I remember early in my research days, running a gel without dye was like trying to parallel park in the dark; you never felt sure about what you were doing. Add Cresol Red, and suddenly, bright orange bands mark every move of your pipette, showing exactly where your DNA is heading. It allows faster, more confident work, which cuts down on mistakes and missed data. Labs in universities, hospitals, and biotech companies have relied on this dye to keep experiments honest, making research more trustworthy.
Cresol Red changes color depending on whether a solution is acidic or basic. Below pH 7.2, it appears yellow; above pH 8.8, it turns purple. In between, you get a mix of shades. I learned this as an undergraduate, watching students mix drops of dye in beakers and guess pH by eye before meters did the work. That color shift makes it a go-to indicator in labs teaching titrations and buffer preparation. Cresol Red doesn’t burn through your skin or gas out the room—relatively safe compared to some alternatives. So it sits well in teaching labs where safety and clarity matter more than cutting-edge speed.
You might spot Cresol Red outside of biology labs. Aquarium hobbyists check water acidity with it, since fish and coral don’t do well if pH swings. In some medical devices, the dye acts as a marker to confirm if a buffer solution has gone bad. Enzyme studies also use it to signal changes as reactions flow from acid to base, or vice versa. The dye doesn’t interfere with enzymes or DNA, which makes it especially valuable when precision counts.
Some researchers now turn to fluorescent markers or digital pH sensors for instant feedback and higher sensitivity. Yet Cresol Red sticks around. Its price stays low, it doesn’t demand fancy equipment, and it rarely fails unexpectedly. For cash-strapped labs, this matters. Even new biotech startups—chasing big discoveries—still fill out their shopping lists with Cresol Red. It’s a reminder that not every solution needs new tech. Sometimes, time-tested tools work fine if applied correctly and thoughtfully.
Cresol Red, for all its strengths, has limits. It’s not ideal in cloudy solutions or where color intensity matters too much. Some newer lab kits blend dyes to improve clarity or switch to alternatives less sensitive to temperature swings. Yet, as budgets squeeze and researchers try to do more with less, there’s merit in keeping affordable, safe, and trustworthy dyes within reach. Supporting more training for new scientists, rather than pushing the latest and greatest tech, could yield better results and save money.
Cresol Red remains part of day-to-day science because it helps make judgment calls faster, keeps costs in check, and allows more hands-on learning. Experience with simple tools often translates to reliable results—and that’s crucial in building trust, repeating results, and moving discovery forward.
Cresol Red shows up on plenty of lab shelves, thanks to its value as a pH indicator and its vivid color changes in buffer recipes. I've handled it during biochemistry classes, watching it tint solutions from yellow to purple, and wondered just how safe it is outside textbook descriptions. Not every chemical needs to come with a skull and crossbones to demand respect. Safety lies in how much we know, and how we act with that info in real situations.
Many assume that anything common in a teaching lab can’t do harm. It’s a mindset that got a few of my classmates in trouble when their gloves weren’t snug or goggles hung around their necks instead of over their eyes. Cresol Red doesn’t scream danger. Still, its manufacturer datasheets label it an irritant. It can sting skin or eyes and cause a bit of a cough if someone breathes in dust or fine powder. Cases of serious toxicity in adults rarely pop up, but I wouldn’t call a chemical “safe” just because emergency rooms don’t see waves of poisonings.
I dug into animal toxicity studies and found that concentrated cresol derivatives have caused harm to mice and rats, including central nervous system effects at high doses. Now, these studies use much greater amounts than any science fair project would. Still, this reminds people that just because humans use tiny amounts doesn’t mean total safety. Small exposures build up if basic lab habits fall apart.
Reliable lab work always calls for thinking ahead and knowing what you handle. I keep gloves handy and wear goggles for anything except the absolute safest classroom demos. Spills dry fast and powders drift, so immediate cleanup works best for keeping your space safe. Rooms where kids or pets roam deserve extra attention; don’t leave dye powders on an open shelf just because they look harmless.
On a daily basis, washing hands after handling Cresol Red and not eating near workspaces prevents accidental swallowing of tiny particles. If it gets on the skin or in the eyes, a good rinse lessens irritation. Open containers only where proper ventilation works—no hoods, no mixing. One professor drilled into us: “treat each chemical as a new risk until you see otherwise.”
Big industries rarely use Cresol Red in quantities that worry environmental groups, but that doesn’t mean waste should pour down the drain. It breaks down slowly, and colored byproducts didn’t feel right to wash into city water. Colleges often train students to collect indicator waste in separate bottles—extra work, but a habit that sets a standard for all dyes, not just the known carcinogens.
Most chemical hazards don’t look like explosions or science fiction. They’re hidden, subtle—like a minor rash, itchy eyes, or a cough that lingers a bit too long. Cresol Red doesn’t belong in a horror story. Still, I’ve seen how the comfort of routine lets people ignore safe practices, making “benign” dyes into problems. Chemistry’s best lesson: Respect every substance and never grow careless just because labels seem bland. It’s the habit of thought—and action—that keeps science safe and open to all.
Cresol Red gets its name called in any biology lab sooner or later. Sometimes, folks treat basic solution prepping like a routine checklist. In my experience, those “small” details make the difference between reliable results and head-scratching errors. Whether you run gels, work with PCR set-ups, or just want a clear marker in your buffer, getting Cresol Red ready takes more than dumping powder in water.
You only need a little Cresol Red powder to make a practical solution, usually around 0.5% by weight. Lab stock bottles come with clear labeling, but one thing gets overlooked: Many powders absorb moisture from air, so always store Cresol Red tightly closed. Measure the powder with a clean scoop or spatula. For example, weighing exactly 0.5 grams and adding it carefully to 100 milliliters of distilled water gives you a consistent stock for most DNA work.
Mixing matters more than people think. The powder usually sits on top of cold water, stubbornly clumping. Swirl with a magnetic stirrer or gently shake in a capped bottle until the powder dissolves completely. Undissolved dye leads to inaccurate pipetting—not to mention expensive mistakes, especially in tight-budget teaching labs.
Cresol Red isn’t something to splash around. Wearing gloves and goggles goes without saying in the real world, especially since stains can linger everywhere. Years back, someone ignored good practice at my old lab, which left purple smears on new countertops for months. Simple actions—quick cleanup, attention to drips, and clear labeling—keep everyone safe and the shelf clean. Safety sheets (SDS) for Cresol Red stress these points, not because of danger but because of the lasting mess.
The solution’s pH affects color and function. People don’t always check. For DNA gels or PCR work, most stick with water and leave it at neutral pH, which works for tracking DNA. If you need the dye for other chemistry, adjust the pH using small drops of acid or base. Always use clean glassware. Dirty flasks or bottles can throw off your pH and mess with results, or worse, contaminate your precious samples.
Storing the solution in an amber bottle helps. Light will fade Cresol Red. If you stick the bottle in the fridge, mark the date, and use within a few months, you’ll dodge most headaches. I’ve watched too many good PCRs fail from old, faded dye. It’s an easy step and costs nothing.
Making Cresol Red solution right the first time makes for smooth days in the lab. From careful measuring to checklists that don’t cut corners on safety, each part adds up to stronger results. Whether you work in research or a teaching setting, starting with good practices sets a tone for every discovery down the line. Real skill in the lab means trusting the steps, not guessing.
Cresol Red sits on lab shelves worldwide, a pH indicator that has helped shape experiments and spark discoveries for decades. Chemists recognize this compound for its vibrant color changes, shifting from yellow to red as acidity changes. The backbone of its chemical structure explains its function and reliability in both classroom and research settings.
At its core, Cresol Red is an organic molecule, not that unlike the dye in your favorite T-shirt but baked with chemistry’s extra complexity. The molecule’s formal name, o-cresolsulfonphthalein, hints at its family tree: three key rings of carbon atoms make up what chemists call a “triarylmethane” structure. These rings are not just for show. Their arrangement gives the molecule both stability and reactivity.
What stands out about Cresol Red’s structure is the arrangement of its functional groups. These are clusters of atoms that decide how the molecule behaves. There’s a sulfonic acid group, which looks like a sulfur atom jumped into a pool of oxygen. Add to this two methyl groups fixed onto two of the carbon rings—a little tweak that changes everything. These groups do more than mark territory on the molecule. They help determine how Cresol Red responds to changes in its environment, especially the hydrogen ion concentration, or more simply, the acidity.
Cresol Red’s structure isn’t just a beautiful chemical curiosity. That careful layout of rings and groups explains why this molecule changes color at just the right pH ranges: from yellow below pH 7.2 to purple above pH 8.8. That makes it perfect for watching the shift in DNA amplification in PCR labs or checking if your aquarium water has gone sour. Years ago, I spent long afternoons in a teaching lab, where a single drop of Cresol Red solution could tell an entire class whether an experiment worked—no advanced instruments needed, just eyesight and a little patience.
This reliability has roots in the molecule itself. The way electrons bounce around those aromatic rings, joined by the sulfonic acid and methyl additions, supports a color change visible with the naked eye. Chemists have measured, modeled, and even drawn out these electron shifts over the years, backing up the everyday use of this little indicator with layers of data. Anyone serious about studying or teaching biology, chemistry, or environmental science has likely run into Cresol Red or its cousins.
Talking about chemical structure shouldn’t stop at the chalkboard. A compound like Cresol Red, made by sulfonation of o-cresol and further chemical steps, deserves attention for how it’s produced and disposed. Many dyes from past decades have earned a bad rap for poor environmental handling. Improved manufacturing controls help keep unintended spills rare, and more labs now recycle or neutralize waste as a matter of standard practice.
For anyone planning to use Cresol Red regularly, safety data sheets remain essential, and proper goggles and gloves still matter. Yet, understanding the molecule—knowing why those methyl groups matter, and what the sulfonic acid group does—offers a deeper respect for this classic indicator. I’ve come to believe that knowing the story behind the color change inspires not just better experiments, but better decisions about chemical stewardship and education.
Cresol Red’s chemical structure, with its triarylmethane base and specialized functional groups, stands as a small but sturdy bridge between academic chemistry and practical, real-world science. Its reliability, color changes, and ease of use continue to support biologists, chemists, and teachers every day. Somewhere on a crowded lab bench, a student will add Cresol Red to a tube and learn to see chemistry in action, one color shift at a time.
Cresol Red may sound like a phrase out of a comic book, but for anyone who’s spent time at the science bench, it’s a trusted pH indicator. This compound helps chemists, biologists, and students figure out the acidity or alkalinity of a solution in real time, telling its story through color.
Drop Cresol Red into a liquid, and it answers a question without words. In acidic conditions, it looks yellow. As the solution shifts toward neutral, it changes through orange to red. In an alkaline world, it ends up purple. These visible signals cut through confusion, making pH measurements approachable even for folks new to lab work. Manuals and charts often show Cresol Red’s color range from about pH 7.2 (yellow) to pH 8.8 (red), though shifts can be seen on either side with strong solutions.
Science leans more and more on sensors and digital meters, but there’s a lesson in not skipping old-school methods. I’ve seen young students light up when a beaker turns bright red or purple, understanding something deep and simple all at once. Cresol Red isn’t just about nostalgia. In settings where electronics can’t go—field stations, packed classrooms, or even disaster zones—these indicators still give fast, clear answers.
Color-based methods also offer a quick check on electronic equipment. If pH meters seem off, a reliable indicator can keep mistakes out of results. This small backup helps spot problems before they cause headaches. Plant biologists tracking soil pH or molecular biologists adjusting buffers both rely on a splash of color to confirm careful work.
Years ago, I helped run chemistry outreach events for local schools. Budget mattered, so buying fancy meters wasn’t an option. Using Cresol Red, we got repeatable results while keeping things fun. Teachers appreciated tools that didn’t break easily, and students remembered what color mapped to which pH range because it felt like magic. For many, that hands-on experience beat any slide show.
Beyond education, Cresol Red shows up during DNA experiments as a tracking dye in gel electrophoresis. It doesn’t just measure pH; it marks the progress of molecules through gels. Labs choose Cresol Red for its stable color changes and low interaction with samples.
No tool works perfectly. In murky or colored solutions, reading the exact shade of Cresol Red gets tough. Solutions high in certain ions alter its behavior, causing false readings for less experienced users. Anyone working with this indicator learns to calibrate with known standards and runs controls.
Cresol Red also falls short in very acidic or basic conditions, where another indicator does the job better. Modern labs teach this as part of the basics, helping newcomers pick the right indicator for each test. Suppliers offer safety sheets, letting researchers use and handle it properly, meeting today’s concern for lab health and environmental impacts.
Cresol Red owes its continued usefulness to simple trust. It teaches students, saves seasoned researchers time, and supports easy science communication. Building awareness about indicator choices and teaching hands-on chemical safety strengthen the science community. As science moves forward, combining digital and visual methods keeps checks and balances in place.
Teaching students to recognize these changes with their own eyes will always matter. Simple indicators like Cresol Red let science stay accessible and memorable, keeping everyone involved in discovery.
| Names | |
| Preferred IUPAC name | 3,3-Bis(4-hydroxy-2-methylphenyl)-2,1λ⁶-benzoxathiole-1,1(3H)-dione |
| Other names |
o-Cresolsulfonephthalein C.I. 75880 |
| Pronunciation | /ˈkriːsɒl rɛd/ |
| Identifiers | |
| CAS Number | 1733-12-6 |
| Beilstein Reference | 132602 |
| ChEBI | CHEBI:86147 |
| ChEMBL | CHEMBL2098867 |
| ChemSpider | 281658 |
| DrugBank | DB11131 |
| ECHA InfoCard | 100.048.737 |
| EC Number | [1914-36-9] |
| Gmelin Reference | 19715 |
| KEGG | C02927 |
| MeSH | D003434 |
| PubChem CID | 11413 |
| RTECS number | GO8925000 |
| UNII | 1Z19F2A3WO |
| UN number | UN2811 |
| Properties | |
| Chemical formula | C21H18O5S |
| Molar mass | 646.70 g/mol |
| Appearance | Dark violet powder |
| Odor | Odorless |
| Density | 1.1 g/cm³ |
| Solubility in water | slightly soluble |
| log P | 1.66 |
| Acidity (pKa) | 7.2 |
| Basicity (pKb) | 7.9 |
| Magnetic susceptibility (χ) | -77.0e-6 cm³/mol |
| Refractive index (nD) | 1.490 |
| Viscosity | Viscous liquid |
| Dipole moment | 9.73 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 310.6 J·mol⁻¹·K⁻¹ |
| Pharmacology | |
| ATC code | V04CX02 |
| Hazards | |
| Main hazards | Harmful if swallowed, causes skin and serious eye irritation. |
| GHS labelling | GHS02, GHS07 |
| Pictograms | GHS05, GHS07 |
| Signal word | Warning |
| Hazard statements | H302 + H312 + H332: Harmful if swallowed, in contact with skin or if inhaled. |
| Precautionary statements | P280-P305+P351+P338-P337+P313 |
| NFPA 704 (fire diamond) | 1-2-0 |
| Flash point | 77 °C |
| Lethal dose or concentration | LD₅₀ (oral, rat): 726 mg/kg |
| LD50 (median dose) | LD50 (median dose): Oral, rat: 2,000 mg/kg |
| NIOSH | SN3850000 |
| PEL (Permissible) | Not established |
| REL (Recommended) | 0.5 mg/L |
| Related compounds | |
| Related compounds |
Phenol Red Thymol Blue Xylenol Orange |
