Naphthalene safety data sheet: what every employer needs to know

Last updated 2026-07-09

What is a safety data sheet, and why does naphthalene need one?

A safety data sheet (SDS) is a standardized document that describes a chemical's hazards and tells workers and emergency responders exactly how to handle it. OSHA defines it in 29 CFR 1910.1200(g) as written or printed material that chemical manufacturers, importers, and distributors must supply with every hazardous chemical they sell. ^[1] The old term was "material safety data sheet" (MSDS). OSHA aligned the rule with the United Nations Globally Harmonized System (GHS) in 2012, and the new format, always 16 sections in a fixed order, became mandatory for downstream employers by June 1, 2016. ^[11]

For a deeper look at how the standard works, our guide to hazard communication covers the full Hazcom program requirements.

Naphthalene (C10H8, CAS 91-20-3) is a solid polycyclic aromatic hydrocarbon that turns up in more workplaces than people expect. Mothballs. Coal-tar products. Asphalt. Certain dyes and resins. Jet fuel handling. Any employer whose workers may be exposed to it has to keep the SDS on file, train workers on it, and make it reachable during every shift. ^[1]

Naphthalene earns a careful SDS because it is both acutely toxic (hemolytic anemia, and cataracts from repeated exposure) and a possible human carcinogen. The International Agency for Research on Cancer classifies naphthalene as Group 2B, possibly carcinogenic to humans. ^[2] That classification lands in Section 11 and drives the PPE and exposure-limit language through the rest of the document.

What are the 16 sections of a naphthalene SDS?

Every naphthalene SDS, no matter which supplier wrote it, follows the GHS section order set out in 29 CFR 1910.1200, Appendix D. ^[1] Here is what each section actually holds for this chemical:

Section	Title	Key naphthalene content
1	Identification	Product name, CAS 91-20-3, supplier contact, recommended uses
2	Hazard identification	GHS pictograms: flame, exclamation mark, health hazard; Signal word: Danger
3	Composition/ingredients	C10H8, MW 128.17, purity range of commercial grade
4	First-aid measures	Eye flush 15+ min, fresh air for inhalation, medical attention for ingestion
5	Fire-fighting measures	Flash point 79-87 °C (174-189 °F); CO2 or dry chemical extinguisher
6	Accidental release	Sweep solid; avoid creating dust; collect in closed containers
7	Handling and storage	Store below 25 °C, away from oxidizers, in tightly closed containers
8	Exposure controls/PPE	OSHA PEL 10 ppm; NIOSH REL 10 ppm; local exhaust; specific respirator
9	Physical/chemical properties	White crystalline solid; melting point 80.2 °C; strong characteristic odor
10	Stability and reactivity	Stable under normal conditions; incompatible with strong oxidizing agents
11	Toxicological information	Hemolytic anemia; IARC Group 2B; LD50 (rat, oral) 490 mg/kg
12	Ecological information	Harmful to aquatic organisms; log Kow 3.37
13	Disposal considerations	Dispose per local/federal regulations; may be hazardous waste
14	Transport information	UN 1334 (solid) or UN 2304 (molten); Class 4.1 Flammable Solid
15	Regulatory information	Listed on TSCA inventory; CERCLA RQ 100 lbs; SARA 313 reportable
16	Other information	Revision date, SDS version, key literature references

Sections 1 through 8 are the ones workers touch day to day. Sections 9 through 16 matter most to your environmental compliance team, to emergency responders, and to anyone shipping the material. All 16 have to be present. A supplier SDS missing any section is non-compliant, and you should flag it to the supplier the day you notice. ^[1]

What are the exposure limits for naphthalene, and where do they appear on the SDS?

Section 8 of the SDS is where every occupational exposure limit lands. Three of them matter for naphthalene, and all three land at the same number.

The OSHA permissible exposure limit (PEL) is 10 ppm as an 8-hour time-weighted average (TWA), set under 29 CFR 1910.1000, Table Z-1. ^[3] The NIOSH recommended exposure limit (REL) is also 10 ppm TWA, with a 15-minute short-term exposure limit (STEL) of 15 ppm. ^[4] The ACGIH threshold limit value (TLV) matches at 10 ppm TWA, but carries a skin notation, meaning dermal absorption is a recognized route in. ^[5]

That skin notation changes how you pick PPE. Naphthalene absorbs through skin and eyes, so gloves and splash goggles are mandatory for any task where contact is plausible. Nitrile gloves give you limited protection. Butyl rubber or laminated film gloves (like Silver Shield) hold up far better for prolonged contact.

OSHA set the 10 ppm PEL decades ago. NIOSH flags naphthalene as a potential occupational carcinogen in its Pocket Guide, which tells you the right posture is keeping exposures as low as feasible rather than just under the PEL. ^[4] Local exhaust ventilation is your first line of defense. Respirators come in only when engineering controls cannot hold the line, or during short jobs where controls are impractical.

For naphthalene vapor above the OSHA PEL, Section 8 usually calls for a half-face air-purifying respirator with NIOSH-approved organic vapor cartridges. Above 10 times the PEL, you move to a full-face piece or supplied air. Always read the specific SDS in front of you, because Section 8 language shifts by supplier and by task.

What health hazards does a naphthalene SDS have to disclose?

Section 2 gives the hazard classification in GHS terms; Section 11 goes deep on toxicology. Between them, here is what a naphthalene SDS should say.

Acute toxicity: Naphthalene is harmful if swallowed (GHS Category 4 oral) and harmful if inhaled. The rat oral LD50 sits around 490 mg/kg. ^[6] Breathing vapors above occupational limits brings headache, nausea, vomiting, and confusion. A high acute dose can trigger hemolytic anemia, especially in people with G6PD (glucose-6-phosphate dehydrogenase) deficiency.

Eye and skin effects: Section 2 should carry an eye irritation classification (GHS Category 2A). Long or repeated skin contact has been linked to dermatitis and, in workers with heavy chronic exposure, to cataracts.

Carcinogenicity: IARC's Group 2B rating (possibly carcinogenic to humans) rests on sufficient evidence in animals and limited evidence in humans, mostly from workers with heavy coal-tar and naphthalene exposure. ^[2] Under GHS, that usually puts naphthalene in Category 2 suspected carcinogen territory. Section 11 should point to the IARC monograph or an equivalent national classification.

Reproductive and developmental toxicity: The evidence is thin. Some animal data show developmental effects at high doses, but most current SDSs do not assign a GHS reproductive toxicity category without stronger human evidence. If your supplier's sheet skips this discussion, that is not automatically a defect. Asking the supplier is still reasonable.

The SDS you receive reflects the classification your supplier reached from the available data. OSHA does not pre-approve SDSs. Accuracy is on the manufacturer or importer. ^[1] If you think a hazard is missing or wrong, start with the manufacturer, and if that goes nowhere, call your regional OSHA office.

What PPE does a naphthalene SDS recommend?

Section 8 of the naphthalene SDS covers exposure controls and personal protective equipment. What you find there should match the specific task rather than sit as a generic list. Most supplier sheets spell out three categories.

Eye and face protection: Chemical splash goggles, not safety glasses with side shields, wherever splash or dust is possible. Add a face shield for large-scale handling.

Skin protection: For incidental contact, nitrile gloves at 8-mil or thicker often show up. For direct or prolonged contact, butyl rubber or laminated polyethylene film gloves protect far better. A lab coat or chemical-resistant apron makes sense where a spill could hit clothing.

Respiratory protection: If engineering controls keep the air below the OSHA PEL of 10 ppm, you need no respirator. Above the PEL, a half-face air-purifying respirator with OV/P100 cartridges is standard. Any respirator use triggers a written respiratory protection program under 29 CFR 1910.134, which includes medical evaluation and fit testing. ^[7]

If you run naphthalene regularly and do not yet have a written safety program that ties SDS requirements to your real procedures, the SafetyFolio program generator can build one that cites the correct CFR standards without eating 15 hours of your week.

For more on osha training requirements when workers handle chemicals like naphthalene, our training guide walks through what Hazcom training must cover and how to document it.

One practical note. PPE selections in an SDS are guidance, not a replacement for your own hazard assessment. Workers cutting, grinding, or crushing solid naphthalene face a much higher inhalation risk than workers standing near sealed containers. Your exposure control plan has to reflect what the task actually does.

What do you do in a naphthalene emergency, per the SDS?

Sections 4, 5, and 6 together form the emergency response part of the SDS.

Section 4 (First aid): For inhalation, move the person to fresh air right away and keep them warm and at rest. If breathing is difficult, trained personnel should give oxygen and transport to a medical facility. For eye contact, flush with plenty of water for at least 15 minutes and remove contact lenses if present. For skin contact, wash with soap and water. Ingestion is more serious: do not induce vomiting, and get medical attention immediately. G6PD-deficient workers face much higher risk of hemolytic anemia and should be identified before any assignment to naphthalene-exposed tasks.

Section 5 (Fire fighting): Naphthalene is a combustible solid with a flash point around 79-87 °C (174-189 °F, depending on form and purity) and an autoignition temperature near 526 °C. ^[6] Suitable extinguishing media are CO2, dry chemical, or foam. Water spray can cool containers, but a direct water stream on a naphthalene fire can spread burning material, so avoid it. Firefighters need self-contained breathing apparatus (SCBA), because combustion throws off carbon monoxide, carbon dioxide, and potentially polynuclear aromatic hydrocarbons in the smoke.

Section 6 (Accidental release): For a small solid spill, sweep or vacuum the material without kicking up a dust cloud and put it in a closed, labeled container for disposal. Keep unprotected people away. Ventilate. Keep the material out of drains and waterways, because naphthalene is harmful to aquatic organisms. ^[6]

Review the emergency contacts in Section 1 of your facility's SDS every quarter. OSHA's Hazcom rule requires manufacturers and importers to staff that emergency number 24 hours a day. The standard does not put that exact duty on downstream employers using the chemical, but posting a number that a live person answers is still worth doing.

How do you store and handle naphthalene safely?

Section 7 of the SDS covers handling and storage. For naphthalene, two things drive the guidance: it has real vapor pressure at room temperature (0.087 mmHg at 20 °C, so it sublimates noticeably even as a solid), and it does not get along with strong oxidizing agents.

Handling: Minimize dust. Run local exhaust ventilation where naphthalene gets weighed, transferred, or processed. Avoid prolonged skin contact. Wash hands before breaks and at the end of the shift. No eating, drinking, or smoking where naphthalene is handled. Ground and bond containers when transferring liquid or molten naphthalene to prevent a static spark.

Storage: Keep it in tightly closed containers in a cool, dry, well-ventilated area below 25 °C. Keep it away from heat, open flames, and strong oxidizers like nitric acid or chlorine. Store it apart from food and feed. Naphthalene sits on the CERCLA hazardous substance list with a reportable quantity of 100 pounds, so any release at or above that threshold has to go to the National Response Center. ^[8]

Inspection tip. A persistent mothball odor in your storage area is a warning that vapor may be building up. The move there is an industrial hygiene air monitoring survey, not a shrug and a fan. Naphthalene's odor threshold runs roughly 0.003 to 0.08 ppm, well below the OSHA PEL, so your nose can smell it long before you are anywhere near the limit. That cuts both ways: smelling nothing does not prove you are safe. Monitoring is the only way to know.

What regulatory requirements apply to naphthalene beyond the SDS?

Section 15 lists regulatory status, and for naphthalene that list runs longer than for most chemicals.

OSHA Hazard Communication (29 CFR 1910.1200): Naphthalene is a hazardous chemical under Hazcom. ^[1] Keep the SDS on file, train workers, maintain a chemical inventory.

TSCA: Naphthalene is on the EPA's Toxic Substances Control Act inventory. It can be manufactured and imported legally, but it carries reporting requirements.

CERCLA: Reportable quantity is 100 pounds (about 45 kg). Any release of 100 pounds or more to the environment has to be reported to the National Response Center at 800-424-8802. ^[8]

SARA Title III: Naphthalene is a SARA Section 313 toxic chemical. Facilities that manufacture, process, or otherwise use it above threshold quantities must file an annual Toxic Release Inventory (TRI) report with the EPA. The processing or otherwise-use threshold is 10,000 pounds per year. ^[9]

DOT: Solid naphthalene ships as UN 1334, Flammable Solid, Class 4.1, Packing Group III. Molten naphthalene ships as UN 2304, same class. Both need a Class 4.1 flammable solid placard once quantities cross placarding thresholds.

State rules vary. California's Prop 65 lists naphthalene as a known carcinogen, added in 2007. ^[10] If your facility is in California or you ship product to California consumers, that carries labeling duties beyond the federal ones.

For small businesses, the SARA 313 and CERCLA pieces get missed most. If you burn through more than a few hundred pounds of naphthalene a year, run the math on whether TRI reporting catches you.

What are your OSHA obligations as an employer who uses naphthalene?

If naphthalene is anywhere in your building, here is the short version of what OSHA wants from you.

First, have the SDS. Under 29 CFR 1910.1200(g)(8), employers must ensure SDSs for each hazardous chemical are readily accessible to employees during each work shift in their work areas. ^[1] "Readily accessible" means during the shift, in the work area, not locked in a cabinet or buried on a drive behind a manager's password.

Second, train workers. Hazcom training under 29 CFR 1910.1200(h) has to cover how to read an SDS, where to find it, what the GHS pictograms and signal words mean, and which protective measures apply to the chemicals in that workplace. ^[1] Training happens before initial assignment and again when a new chemical hazard shows up.

Third, maintain a chemical inventory. Your written Hazard Communication Program must list every hazardous chemical present. Naphthalene goes on that list, paired with its SDS.

Fourth, label containers. Every naphthalene container needs a label with the product identifier, a signal word, hazard statements, pictograms, and supplier contact. The original manufacturer label satisfies this. Transfer naphthalene to a secondary container and that one needs a label too, unless the person who filled it uses it immediately and keeps it under their control.

Fifth, if task assessment or air data suggests exposures may approach the PEL, monitor and put engineering controls in place. Documented exposure assessments are not explicitly required by the general industry Hazcom standard, but they are good practice, and OSHA inspectors look for them once a violation is alleged.

Building a Hazcom program from scratch? Our hazard communication guide walks through everything the written program has to contain. An incident report should also document any naphthalene exposure event, in case it triggers OSHA recordkeeping.

How do you read and use a naphthalene SDS effectively in the real workplace?

Knowing the 16 sections exist is one thing. Using the SDS as a working document is another.

Practical approach. Post a one-page job safety analysis (JSA) at the point of use that pulls the key items from Sections 2, 4, 7, and 8. Nobody should be flipping through a 12-page SDS mid-task. The SDS stays on file for reference and emergencies; the JSA is the daily tool.

Verify the SDS is current. Manufacturers must update the sheet when significant new hazard information turns up and provide the updated version to employers within three months of learning of it. ^[1] Check the revision date in Section 16. Working from an SDS more than five years old? Ask your supplier for a current copy.

Confirm the SDS matches what you actually have. Section 3 (Composition) should describe the product you bought. Technical-grade naphthalene may carry small amounts of other polynuclear aromatics, and those belong in Section 3. A pure-grade product has a different impurity profile.

Bridge the SDS to your training. OSHA requires training specific to the chemicals actually present in the work area. ^[1] Handing workers a generic SDS and saying "read this" does not meet the standard. Your training should walk through what Sections 2, 4, 7, and 8 say about naphthalene in particular.

If your written Hazcom program or training records are in rough shape, the SafetyFolio program generator can build a compliant written program in about 15 minutes, pulling the correct CFR references and leaving room to attach chemical-specific SDS information.

Want to go deeper on training? Our osha training article explains what counts as compliant Hazcom training and how to document it.

Where can you get a naphthalene SDS, and how do you know if it is OSHA-compliant?

The supplier of the naphthalene you bought has to provide an SDS with the first shipment and on request any time after that. ^[1] Most major chemical suppliers post their SDSs online for free download.

For reference sheets you use for training, research, or gap-checking your supplier's document, three sources are reliable:

NIH's PubChem database (pubchem.ncbi.nlm.nih.gov) keeps GHS hazard classifications and property data for naphthalene that you can hold against your SDS. ^[6]

Sigma-Aldrich (now MilliporeSigma) publishes detailed SDSs for laboratory-grade chemicals that get cited as reference examples all the time.

The CDC's NIOSH Pocket Guide to Chemical Hazards entry for naphthalene gives you exposure limits, symptoms, and first-aid language that a compliant SDS should carry. ^[4]

So how do you tell if an SDS is OSHA-compliant? Check for all 16 sections, in order. Confirm Section 2 has GHS pictograms and a signal word. Confirm Section 8 lists the OSHA PEL and at least one other occupational exposure limit. Confirm Section 1 has a 24-hour emergency phone number. Miss any of those and the sheet fails 29 CFR 1910.1200, Appendix D. ^[1]

One honest caveat. OSHA keeps no registry of "approved" SDSs. The agency sets the format and holds manufacturers responsible for accuracy. An SDS can look perfect and still carry outdated toxicology or a missing hazard classification. Cross-checking Section 11 against IARC, NIOSH, and EPA data for your specific chemical is the only real verification, and most small employers reasonably lean on major, reputable suppliers to get it right.

Frequently asked questions

What is a safety data sheet (SDS) in simple terms?

A safety data sheet tells workers, employers, and emergency responders everything they need to handle a chemical safely. It lays out the hazards, storage and handling, what PPE to wear, and what to do when something goes wrong. OSHA requires one for every hazardous chemical in the workplace under 29 CFR 1910.1200, in a fixed 16-section format.

What is the OSHA PEL for naphthalene exposure?

OSHA sets the permissible exposure limit for naphthalene at 10 ppm as an 8-hour time-weighted average, under 29 CFR 1910.1000, Table Z-1. NIOSH also recommends 10 ppm TWA with a 15-minute STEL of 15 ppm. Both limits appear in Section 8 of the naphthalene SDS.

Is naphthalene classified as a carcinogen?

IARC classifies naphthalene as Group 2B, possibly carcinogenic to humans, based on sufficient animal evidence and limited human data, mostly from coal-tar worker studies. Section 11 of a compliant naphthalene SDS should disclose this. California's Prop 65 lists it as a known carcinogen, which can require extra labeling.

What PPE should workers wear when handling naphthalene?

Section 8 of the SDS calls for chemical splash goggles for the eyes, butyl rubber or laminated film gloves for the skin (nitrile only for incidental contact), and a half-face air-purifying respirator with organic vapor cartridges if concentrations top the OSHA PEL of 10 ppm. Any respirator use requires a written respiratory protection program under 29 CFR 1910.134.

What is the difference between an MSDS and an SDS?

MSDS (material safety data sheet) was the older format with no fixed section order, used before 2012. SDS is the current 16-section GHS-aligned format OSHA phased in, with full compliance for downstream employers by June 1, 2016, under the revised Hazard Communication Standard (29 CFR 1910.1200). The content overlaps, but the SDS format is standardized worldwide, so you find critical information faster.

What is naphthalene's reportable quantity under CERCLA?

Naphthalene has a CERCLA reportable quantity of 100 pounds. Any accidental release of 100 pounds or more to the environment must be reported immediately to the National Response Center at 800-424-8802. Section 15 of a compliant naphthalene SDS lists this.

How do you store naphthalene to meet SDS requirements?

Section 7 directs storage in tightly closed containers in a cool, dry, well-ventilated area below 25 °C. Keep it away from strong oxidizing agents and heat sources, and separate from food. Because naphthalene sublimates at room temperature and has a very low odor threshold, adequate ventilation matters even in cool storage areas.

What do you do if a worker is exposed to naphthalene vapor?

Per Section 4 of the SDS, move the person to fresh air right away and keep them at rest. If breathing is labored, trained personnel should give oxygen and transport to a medical facility. Workers with G6PD deficiency face elevated risk of hemolytic anemia from naphthalene and should be identified before any assignment to naphthalene-handling tasks.

Do employees have a right to see the naphthalene SDS?

Yes. Under 29 CFR 1910.1200(g)(8), employers must keep SDSs readily accessible to employees during each work shift in their work area. Employees cannot be forced to ask a supervisor or wait for access. SDSs can live electronically as long as nothing blocks access during the shift and a backup exists for power or equipment failure.

Does SARA 313 apply to naphthalene?

Yes. Naphthalene is a SARA Section 313 toxic chemical. Facilities that manufacture, process, or otherwise use 10,000 pounds or more per year must file an annual Toxic Release Inventory report with the EPA. Small users below the threshold are exempt from TRI reporting but still carry OSHA and CERCLA obligations.

What fire hazard information does a naphthalene SDS contain?

Section 5 covers fire hazards. Naphthalene has a flash point around 79-87 °C and an autoignition temperature near 526 °C, and it is classified as a flammable solid (UN 1334). Use CO2, dry chemical, or foam to extinguish. Firefighters must use SCBA, because combustion products include carbon monoxide and potentially polynuclear aromatic hydrocarbons.

How often should a naphthalene SDS be updated?

OSHA requires manufacturers and importers to update the SDS when significant new hazard information appears and to provide the updated version to employers within three months of learning of the change. Check Section 16 for the revision date. If your SDS is more than five years old, request a current version from your supplier.

What training is required for workers who handle naphthalene?

Under 29 CFR 1910.1200(h), Hazcom training must cover where to find and how to use the SDS, how to read GHS labels, the specific hazards of naphthalene (inhalation, skin absorption, carcinogenicity), and protective measures. Training happens before initial assignment and when a new chemical hazard appears. Generic chemical training does not satisfy the chemical-specific requirement.

Can naphthalene SDS requirements apply to small businesses?

Yes. The Hazard Communication Standard applies to all employers whose workers may be exposed to hazardous chemicals, regardless of company size. There is no small-business exemption. Even a shop with one worker using naphthalene-containing products must keep the SDS accessible, train the worker, and maintain a written Hazcom program.

Sources

1. OSHA, Hazard Communication Standard (29 CFR 1910.1200): SDS requirements, 16-section format, employee access, training, labeling, and manufacturer update duties under Hazcom
2. IARC, Monograph on Naphthalene, Volume 82: IARC classifies naphthalene as Group 2B, possibly carcinogenic to humans
3. OSHA, 29 CFR 1910.1000 Table Z-1 Air Contaminants: OSHA PEL for naphthalene is 10 ppm as an 8-hour TWA
4. NIOSH, Pocket Guide to Chemical Hazards: Naphthalene: NIOSH REL for naphthalene is 10 ppm TWA with a 15-minute STEL of 15 ppm; designated potential occupational carcinogen
5. ACGIH, TLV-TWA Documentation for Naphthalene: ACGIH TLV for naphthalene is 10 ppm TWA with a skin notation
6. NIH PubChem, Naphthalene Compound Summary (CID 931): Rat oral LD50 approximately 490 mg/kg; flash point 79-87 °C; autoignition temperature approximately 526 °C; log Kow 3.37
7. OSHA, Respiratory Protection Standard (29 CFR 1910.134): Any employer whose workers use respirators must have a written respiratory protection program including medical evaluation and fit testing
8. EPA, CERCLA Hazardous Substance List: Naphthalene: Naphthalene CERCLA reportable quantity is 100 pounds; releases at or above this amount must be reported to the National Response Center
9. EPA, Toxic Release Inventory (SARA Section 313) Chemical List: Naphthalene is a SARA 313 reportable chemical; processing/otherwise use threshold is 10,000 pounds per year
10. California OEHHA, Proposition 65 Listed Chemicals: California Proposition 65 lists naphthalene as a known carcinogen (added 2007)
11. OSHA, Hazard Communication publications for small employers: GHS-aligned SDS format with 16 sections became mandatory for downstream employers by June 1, 2016