Chemical Education Today
CLIP, Chemical Laboratory Information Profile “Only when you know the hazards, can you take the necessary precautionary measures.”
Paraformaldehyde HOCH2(OCH2)nCH2OH
CAS No.: 30525-89-4
Synonyms: paraform, polyoxymethylene
Physical Properties
White powder Vapor pressure at 20 °C: 1.5 Torr Decomposes at: ~120 °C
Exposure Limits OSHA PEL: Action level: ACGIH TLV: STEL/C
0.75 ppm STEL 2 ppm 0.5 ppm NA 0.3 ppm
Hazardous Characteristics
Overall toxicity 3
Flamma- bility 2
Destructive to skin/eye 3
Absorbed through skin? Yes
Sensi- tizer? Yes
Self- reactive? No
Incompatible with: Oxidizing agents, hydrochloric acid*
0: None (or very low); 1: Slight; 2: Moderate; 3: High; 4: Severe. *Reactivity Hazards
Finely powdered paraformaldehyde is a dust explosion hazard. Paraformaldehyde reacts with hydrochloric acid forming very toxic bis(chloromethyl) ether. The reaction with strong oxidizing agents is violent, less so with weaker oxidizing agents. With NaOH the Cannizzaro reaction is strongly exothermic. In the presence of a catalyst, the reaction with phenol is a violently exothermic runaway reaction. See Bretherick’s Handbook of Reactive Chemical Hazards for details and for other incompatibilities.
Cited as known to be or reasonably Yes, by anticipated to be carcinogenic in NTP-11? vapor inhalation
Identified as a reproductive toxin in Frazier and Hage, Reproductive Hazards of the Workplace? Possibly
Typical symptoms of acute exposures:
In the eyes, pain, inflammation, blurred vision. If inhaled, discomfort, sore throat, coughing, shortness of breath, lung edema. On the skin, inflammation, pain, burns, dermatitis. If ingested, sore throat, abdominal pain, vomiting, diarrhea. Principal target organ(s) or system(s):
Eyes, respiratory system, skin, liver, kidney
Storage Requirements
Store with other flammable, combustible poisons separated from oxidizing agents and ignition sources in a cool, dry, well-ventilated locked location.
Additional Remarks
Paraformaldehyde vapor is formaldehyde; the exposure limits cited above are those established for formaldehyde. Vapors of formaldehyde mix readily with air and are explosive. When heated, paraformaldehyde releases more formaldehyde. Even at ordinary temperatures, the concentration of formaldehyde vapor from paraformaldehyde is approximately 1900 ppm and therefore greatly exceeds the limits for formaldehyde as established by OSHA and ACGIH. Accordingly, paraformaldehyde users will be likely to be over-exposed to formaldehyde unless appropriate precautions are rigidly maintained; for details see the MSDS for paraformaldehyde. Symptoms of lung edema are not manifest immediately in victims who have inhaled vapors of formaldehyde from paraformaldehyde; some hours may elapse first; physical effort can exaggerate these symptoms. Rest is essential for persons exposed to excess vapor or mist. For Action Level details, see Title 29 of the Code of Federal Regulations, part 1910, section 1048.
Notes
ReadMe
This Chemical Laboratory Information Profile is not a Material Safety Data Sheet. It is a brief summary for teachers and their students that describes some of the hazards of this chemical as it is typically used in laboratories. On the basis of your knowledge of these hazards and before using or handling this chemical, you need to select the precautions and first-aid procedures to be followed. For that information as well as for other useful information, refer to Material Safety Data Sheets, container labels, and references in the scientific literature that pertain to this chemical. Reproductive toxins
Some substances that in fact are reproductive toxins are not yet recognized as such. For the best readily available and up-to-date information, refer to “DART/ETIC”. See the TOXNET home page at http://toxnet.nlm.nih.gov/. Note that some of the data in DART/ETIC have not been peer-reviewed. See also Frazier, Linda M.; Hage, Marvin L. Reproductive Hazards of the Workplace; Wiley: New York, 1998; and Shepard, T. H. Catalog of Teratogenic Agents, 9th ed.; Johns Hopkins University Press: Baltimore, MD, 1998. Abbreviations
ACGIH TLV—American Conference of Governmental Industrial Hygienists–Threshold Limit Value. C—Ceiling. CAS—Chemical Abstracts Service. mg/m3—milligrams per cubic meter. NA—Not applicable. NE—Not established. NI—No information. NTP‑11—National Toxicology Program, Eleventh Annual Report on Carcinogens. OSHA PEL—Occupational Safety and Health Administration– Permissible Exposure Limit. ppm—parts per million. STEL/C—Short-term exposure limit and ceiling. Prepared by: Jay A. Young
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Date of preparation: January 8, 2009
Journal of Chemical Education • Vol. 86 No. 3 March 2009 • www.JCE.DivCHED.org • © Division of Chemical Education
