"Ventilation plays a key role in maintaining an Aspergillus free environment."

1. An Aspergillus rich culture in the environment.
2. Inadequate ventilation in the environment.
3. Improperly packaged marijuana being stored.
4. Large quantities of marijuana being stored.
5. Inadequate housekeeping in the evidence/property area.
6. Inadequate use of personal protective equipment.

Ventilation plays a key role in maintaining an Aspergillus free environment.  Property and evidence facilities should have a separate, negative pressure ventilation system that vents outside the building.  Inadequate ventilation promotes the multiplication of microorganisms which in turn allows these them to become highly concentrated.  Where HVAC systems are in place, the filters must be replaced on strictly scheduled intervals.  Dirty, contaminated filters reduce the effective filtration and causes microorganisms to reproduce and recirculate into the work area.²  Suitable clean, filtered outside makeup air must be provided. While local codes may vary, a minimum should be at least 10 liters per second per occupant.  Inadequate ventilation systems should be upgraded as soon as possible.

Marijuana is often submitted to the evidence facility in burlap or paper bags.  Unfortunately, these packaging materials provide an excellent matrix for the escape of Aspergillus spores.  The real problem with marijuana, as a decomposing plant material, is the moisture content left in the plant.  Living marijuana plants contain about 80% water.  Fungi cannot grow below 15% moisture content.  Perfectly dried marijuana contains about 10% - 15% water.³  Most growers market their product above 15% since it is sold as soon as possible and by weight and not volume.  This is the product that is submitted to the evidence facility.  In addition to the yet moist packaged marijuana is the whole plant that has been pulled up from a cultivation site.  Both scenarios present the impossible question: how much moisture content is still present in any given amount of marijuana being submitted into evidence?  The answer is unknowable.  The only adequately dried marijuana is that which is brittle.  Since the moisture content is an uncontrollable factor, packaging becomes the only solution to the problem.

Proper packaging presents its own dilemma.  Burlap and paper provide an inadequate barrier for Aspergillus spores.  The only material left is an impermeable bag.  Such bags are usually manufactured of plastic.  Plastics create the problem that moisture-laden marijuana enclosed in such material will eventually decompose into a material equivalent to mush and soup.  Once in this state, its evidentiary value may come into question.  Management must make the decision regarding packaging versus the potential for introduction of Aspergillus spores into the storage facility.

In fact, most agencies store quantities of marijuana that may not need to be maintained in their facility.  Firstly, marijuana should not continue to be stored if the case has been adjudi cated.  Such marijuana should be sent for destruction
as soon as reasonably possible.  Secondly, agencies should make a commitment to maintain only the amount of marijuana required by law to adjudicate the case.  Why not document and photograph the excessive amounts of marijuana, take necessary samples for laboratory analysis, and then destroy it.  Considering the potential health hazards presented by quantities of marijuana, why take the risk of becoming infested with Aspergillus spores.  All efforts should be made to reduce the amount of marijuana being held in the evidence facility.  Evidence should be inspected as it is delivered and cleaned and sealed appropriately before being stored.

Housekeeping procedures present one of the best solutions and preventative measures available for contamination problems in the evidence facility.  If a facility is suspected of being contaminated, corrective measures can be taken.  Discard all porous building materials and property that are visually contaminated with fungi.  Wash the entire storage area down with a dilute bleach solution (1 cup per gallon of water).  All smooth surfaces potentially contaminated with fungus should be included in the decontamination.  Workers must be provided with adequate personal protective equipment including protective clothing, gloves, goggles, shoe covers and particulate masks.

Once decontamination is complete, seal all porous surfaces such as concrete walls to eliminate dust and debris settling points.  These settling areas provide reservoirs for microbial growth.  Vacuum and wet wipe (with an antifungal agent) all building and content surfaces in the evidence facility.⁴

It is imperative that a regular schedule for housekeeping be developed that includes vacuuming and surface cleaning with appropriate disinfectants.  This may require an attitude upgrade on the part of the evidence facility personnel.  Housekeeping should never be viewed as an extra responsibility.  It is an integral part of her/his job and is a standard part of operations.

Personal protective equipment is the mainstay of protection for personnel in providing necessary protective barriers between them and a potentially damaging material.  When handling or storing marijuana, long sleeves, gloves and a dust/particulate respirator should be wom.  Disposable sleeves can be purchased through many safety equipment suppliers.  A jump suit or protective coat/smock will provide such protection.  Latex gloves are adequate but a no powder vinyl or nitrile glove may be preferable where latex sensitivity is a concem.

While a standard dust/particulate mask is adequate, some individuals may prefer to use a High Efficiency Particulate (HEPA) mask.  Personnel who exhibit microbial sensitivities are often more confident of protection with this type of mask.  As added protection, eye goggles (chemical splash) can be wom to assure that no Aspergillus spores can lodge in the moist areas of the eyes while handling marijuana.

As previously noted, personal protective equipment should always be wom during decontamination of the storage facility.  Management must encourage all employees to review labels on disinfecting agents prior to use.  Adequate ventilation must be provided when performing decontamination.

An ancillary problem related to marijuana storage is the problem of rodents,
Unfortunately, mice like to eat and nest in marijuana.  The most obvious sign of mouse infestation is the appearance of droppings.

The health hazard comes with the infestation by the common deer mouse.  This mouse is prevalent throughout the United States.  It is also a carrier of the hantavirus which attacks the respiratory system.  This virus caused the death of a number of people in the Four Corners area of the country a few years ago and cases continue to be reported to this day.

The hazard is associated with an accumulation of mouse droppings and subsequent exposure to those droppings when swept up or moved.  If the property and evidence facility displays an abundance of mouse droppings, measures should be taken to eliminate these rodents.  Personal protective equipment should be wom during any cleaning procedures.

All that remains is for evidence facility personnel and their management to recognize the hazards of marijuana storage.  Once the awareness is there, preventative steps can be taken to ensure a healthier work environment.

Author Nancy Masters helped develop and taught courses in Latent Print field for the California Criminalistics Institute, and has served as Safety Officer for the Bureau of Forensic Service, CA DOJ.  She helped create the current Clandestine Laboratory Manual and has received the Govemor's Safety Award.  She has addressed law enforcement groups throughout the U.S. and in Israel.  She has a B.A. in Police Science and a Teaching Credential.  Her publications include a recent F.B.I. Law Enforcement Bulletin article and her first book is: Safety for the Forensic Identification Specialist.