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Overview: Dissection of preserved specimens is an essential component of many science curriculums. Unfortunately, dissection can pose a significant exposure risk to formaldehyde. Most specimens currently available are fixed in formaldehyde and then transferred to a holding solution such as Carosafe®. The abdominal cavity retains a significant amount of formaldehyde. Figure 1 shows the result of measurements made on the fetal pig.

Figure 1

What constitutes a "safe" level of exposure is difficult to determine. Most specimen suppliers are using the Occupational Health and Safety Administration’s (OSHA) Formaldehyde Standard, 20 CFC PART 1910.1048. This standard is an occupational standard developed for adults in workplace settings and is subject to a complex rulemaking process. The standard does not reflect current research and certainly should not be applied to students. The National Institute for Occupational Safety and Health (NIOSH) conducts research on safety and health issues and makes recommendations to OSHA.

Figure 2 compares the three most common organizations’ exposure standards for formaldehyde:
Figure 2
Formaldehyde Exposure Standards
Standard TWA STEL C

ACGIH - - 0.3ppm

OSHA 0.75ppm 2ppm -

NIOSH 0.016ppm - 0.1ppm

TWA- This defines the level of exposure that "nearly all workers may be repeatedly exposed, day after day, without adverse effect." (TLV-TWA). This is a weighted average assuming an 8-hour workday and a 40-hour workweek.

STEL- This defines the level that workers may be exposed to for a short time (15 minutes).

C- This defines the "ceiling" exposure. This is the concentration "that should not be exceeded during any part of the working exposure".

ACGIH- The American Conference of Governmental Industrial Hygienists is a professional organization, which establishes consensus standards, which are published annually. OSHA adopted many of these standards as its initial standards.

The OSHA TWA value is almost 50 times greater than the value recommended by NIOSH. More importantly, the ceiling limit recommended by NIOSH is only 0.1 ppm. All the specimens we tested (see figure 1) out gassed levels of formaldehyde equal to or in excess of the NIOSH ceiling value. Formaldehyde exposure is the most common type of chronic exposure experienced by students in laboratory settings. Clearly, the use of any specimen capable of out-gassing formaldehyde should be avoided.

Additionally, museum specimens pose a significant spill risk. A spill of a container containing concentrated formaldehyde will expose the person cleaning up the spill to an unacceptable level of formaldehyde. If the container is large, the level may reach a concentration known as Immediately Dangerous to Life or Health (IDLH). The IDLH concentration for formaldehyde is 20 ppm. In some cases rooms have had to be closed and emergency response teams summoned when containers of formaldehyde were broken.

Formaldehyde is a select carcinogen, a sensitizer, an allergen and a corrosive. An excellent MSDS for formaldehyde

Alternatives: The best alternative we have found to formaldehyde is Streck Tissue Fixative (S.T.F.^TM). This is a Child's Pharmaceutical preservative originally developed in England and marketed in the U.S. by Streck Laboratories of Omaha Nebraska. Specimens preserved in S.T.F.^TM are available from Nebraska Scientific (800-228-7117). We have tested the fetal pig and detected no formaldehyde. The quality of the specimen was superior to all others we tested. The specimen does have a limited shelf life but we did not detect any deterioration or mold over the two-month period we dissected. Unfortunately S.T.F.^TM specimens are not readily available for the bullfrog or the cat and the cost of the cat is prohibitively expensive. Sargent-Welch provides a formaldehyde-free specimen called "Safe-Way". We have tested this specimen and did not detect formaldehyde. The specimen was slightly discolored and the tissue was "rubbery". The MSDS lists 1-2% propylene glycol and 0.1-0.3% phenol. The specimen has a slight phenol odor similar to Noxzema®. Freeze dried specimens are available from Wards. The specimen we dissected did not outgas formaldehyde but was difficult to rehydrate and mold developed. Carolina Biological has recently introduced Carosafe 2000, a new nonformaldehyde preservative. We are currently evaluating the specimens and the preservative. No MSDS is available as the preservative is characterized as nonhazardous.

Suggestions:
   ** Dispose of all specimens which contain any formaldehyde
   ** Review the MSDS for new purchases and request a sample specimen before ordering. We highly recommend the S.T.F.^TM preserved specimens from Nebraska Scientific
   ** Dispose of all museum specimens in glass containers larger than a pint. These represent a significant spill risk. If you decide to retain these specimens enclose them in a plastic secondary container. Put electrical tape around the lid of all the pint containers to prevent out gassing.
   ** Develop and implement a spill control plan for formaldehyde spills