Appendix P - Formaldehyde Standard Operating Procedure

A. Introduction
This document outlines general guidelines to be followed when handling animal and human tissues where formaldehyde is used as component of a tissue preservative. The amount of formaldehyde in the preservatives varies from "trace amounts" in Carosafe mixtures (used by Carolina Biological for the preservations of cats) to 5-29% in cadaver embalming fluid.

1. The cats from Carolina Biological (and other 'Carosafe' specimens) are initially preserved in formaldehyde, but then are washed and immersed in a water/propylene glycol solution. Only residual amounts of formaldehyde remain. Care should be taken when first removing the cats from the bags that come from Carolina, including appropriate PPE (gloves, lab coat, respirator, eye protection, and snorkel hood). Students and instructors should be trained in the use of the snorkel hoods and gloves during cat dissection.

1. Pure formaldehyde is a gas at room temperature, but is available from chemical supply companies in 37% aqueous stock solution. Typically, when dilutions are made of this stock solution, it is referred to as '100%'. Tissue fixative solutions that are 10% of the stock solution are thus 3.7% formaldehyde. Phenol, glycerin and methyl alcohol are other typical components of specimen fixative. Formaldehyde dissolved in methanol is referred to as formalin, but formalin and formaldehyde are often (mistakenly) terms used interchangeably.

B. Processes where potential significant formaldehyde exposure can occur

1. 1. 1. 1. Preparation of embalming/fixative/specimen moisturizing solutions:
   2. Performed by the lab coordinator or anatomy lab instructor(s)
   3. Formaldehyde solutions (5%) are sprayed on cadavers and their linen covers to prevent tissue desiccation and fungal growth from week to week and over the summer. Since a concentrated solution of formaldehyde must be diluted to make these solutions, particular care should be taken in the mixing of the solution. Make all such solutions in a chemical fume hood (such as that in 47C), carefully following fume hood procedures. Skin and eye protection should be worn during this process.
2. Initial and weekly opening/uncovering cadavers and other specimens; maintenance fluids
3. Performed by the lab coordinator, anatomy lab instructor(s), and/or student lab assistant(s).
4. Prior to the cadaver's arrival at EMU, 5% percent formaldehyde solutions are injected into the vascular system and the higher concentrations are pumped into the abdominal cavity. Thus, both during the opening of the cadaver bag and situating it on the cadaver tables after arrival at EMU, and during the opening of the abdomen are times of potential exposure, and should be done with appropriate precautions and PPE, on the cadaver dissection tables.

1. Wetting solutions containing phenol (but not formaldehyde) are used throughout the dissection period, and should be used with caution. However, because they do not contain formaldehyde (or any other highly volatile toxin) can be done without PPE.

1. Five percent formaldehyde solutions ("maintenance solutions") are used to maintain cadavers from week to week, and over the summer and winter break months, to prevent fungal and bacterial growth. Thus, at the beginning of each cadaver lab period, assigned persons will open the cadaver cabinet(s) and remove the waterproof tarp and linen cloth covering the body(s), with potential exposure to significant air-born formaldehyde. This process requires the use of gloves, lab coat, respirator, and non-vented goggles. The tarps and linens will be stored in plastic sealed containers, and placed in the ventilated closet (47G).

C. All personnel working with formaldehyde, including formaldehyde-processed specimens, must be fitted with a respirator and vent-less goggles, as described in Appendix O of the EMU Chemical Hygiene Plan "Respiratory Protection Program". Formaldehyde exposure monitoring will be performed each year and the results reported to all students in the cadaver dissection courses, and the affected staff and faculty.