300 Journal of Chemical Education  •  Vol. 86 No. 3 March 2009  • www.JCE.DivCHED.org  • © Division of Chemical Education

Chemical Education Today

“Only when you know the hazards, can you take the necessary precautionary measures.”

Paraformaldehyde HOCH2(OCH2)nCH2OH CAS No.: 30525-89-4Synonyms: paraform, polyoxymethylene

Physical Properties Exposure LimitsWhite powder OSHA PEL: 0.75 ppm STEL 2 ppmVapor pressure at 20 °C: 1.5 Torr Action level: 0.5 ppm Decomposes at: ~120 °C ACGIH TLV: NA STEL/C 0.3 ppm

Hazardous Characteristics Overall Flamma- Destructive Absorbed Sensi- Self- Incompatible with: toxicity bility to skin/eye through skin? tizer? reactive? Oxidizing agents, hydrochloric acid* 3 2 3 Yes Yes No

0: None (or very low); 1: Slight; 2: Moderate; 3: High; 4: Severe.

*Reactivity HazardsFinely 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 Identified as a reproductive toxin in Frazier and Hage, anticipated to be carcinogenic in NTP-11? vapor inhalation Reproductive Hazards of the Workplace? PossiblyTypical 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 concentra-tion 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.

NotesReadMeThis 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 ToxinsSome substances that in fact are reproductive toxins are not yet recognized as such. For the best readily available and up-to-date informa-tion, 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.AbbreviationsACGIH 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—Na-tional 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 Date of preparation: January 8, 2009

CLIP, Chemical Laboratory Information Profile