A work hazard presently facing mailroom workers is the potential transmission of Bacillus anthracis (Anthrax). HealthChem (HCI) evaluates, designs and installs air-borne disease control systems based on criteria recommended by Centers for Disease Control (CDC) Interim Recommendations for Protecting Workers from Exposure to Bacillus anthracis in Work Sites Where Mail Is Handled or Processed. These interim recommendations are used to develop a comprehensive program to reduce potential skin or inhaled exposures to B. anthracis spores. The CDC recommendations do not address instances where a known or suspected exposure has occurred.

The CDC recommendations use the following categories to describe measures that should be implemented to prevent potential exposures to B. anthracis spores:

× Engineering controls
× Administrative controls
× Housekeeping controls
× Personal protective equipment for workers

HCI will work with your operations and maintenance groups to evaluate which processes, operations, jobs or tasks would be most likely to result in an exposure should a contaminated envelope or package enter the work area.

Engineering Controls for Mail-Handling/Processing Sites

B. Anthracis spores can be aerosolized during the operation and maintenance of high-speed mail-sorting machines, potentially exposing workers and possibly entering HVAC systems. HEPA vacuum cleaners and HEPA-filtered exhaust ventilation should be installed in settings where such machinery is in use.
Engineering controls to reduce routes for spore transmission include fresh-air dilution, pathogen removal by ultra-high efficiency particulate air filtration, and disinfection by UV irradiation. Potentially contaminated rooms must incorporate pressure and ventilation controls to maintain:

× Fresh-air ventilation and mixing to dilute and remove air-borne spores
× Control of airflow through the room
× Negative relative pressure for air inflow
× Air exhaust to outdoors away from intakes

HCI’s ventilation engineer should determine optimum facility airflow. Air exhaust systems connected to common headers must be sealed, and negative duct pressure maintained. Maintaining negative pressure relative to the adjacent corridor assures that potentially contaminated air does not enter the building's common areas.

Administrative and Housekeeping Controls

HCI can help develop administrative and housekeeping procedures to limit people working near mail-sorting equipment and places where mailbags are unloaded or emptied. Maintenance personnel should be trained to not dry sweep or dust where particles may be generated.

Infectious Bacilli Removal by High Efficiency Particulate Air (HEPA) Filtration

Anthrax, tuberculosis and fungal respiratory diseases may be transmitted by airborne infectious particles carried at low ambient concentrations. HEPA filters have been shown to be effective in clearing the air of Aspergillus spores, which are about the same size as other spores and bacilli. HealthChem local and multi-zonal HEPA filtration systems continuously remove up to 99.97% of airborne pathogens larger than 0.3 microns. Installing dedicated HEPA filter modules and return air registers, which are validated via smoke tests and airflow models, is a cost-effective way to reduce the spread of infectious particles throughout the room. An engineered HEPA filtration system optimizes:

× Required air recirculation rate
× Particle removal efficiency
× Air flow pattern
× Relative negative pressure
× Maintenance and monitoring requirements

The air filtration system includes easily replaceable pre-filters to remove relatively large room dust particles, and passes the supply air through the ultra-high efficiency filter modules to remove remaining droplet nuclei smaller than 5 microns. It is also safer to HEPA filter or UV disinfect the air prior to exhaust to the outside environment.

Germicidal UV Irradiation

Irradiation by ultra-violet (UV) light has proven to effectively kill pathogens. Effective and safe UV germicidal irradiation (UV-C) is powerfully germicidal and ensures pathogen disinfections. Key irradiation design factors include:

× Lamp placement
× Radiation dosage rate
× Control of dosage time
× Access for checking and cleaning bulbs

UV-C is most effective against airborne organisms that are most likely to penetrate and be retained in deep pulmonary spaces. Larger pathogen particles fall to the floor or are removed by HEPA filters.

Validation, Training and Maintenance Services

After we've installed engineering controls, HealthChem will validate the completed Anthrax engineering controls to assure that the design requirements are satisfied. Via interactive training programs, HCI will assist operation and maintenance personnel to implement the recommended procedures.

To maintain your engineered system operation and procedural charges, HealthChem provides a service contract that includes system maintenance and periodic system testing and certification.

Reference Projects - Airborne Disease Control Systems

Newark Community Health Centers, Newark, New Jersey

To reduce chances of tuberculosis infection in two primary-care clinics, we designed multi-zonal disease transmission control systems. Each zone has a dedicated recirculation fan with supply and return duct-work to pre-filters and multiple HEPA filtration modules. UV-C disinfection lamps are applied in waiting rooms and controlled zones are monitored via an Iso-alert panel.

Community Hospital of Brooklyn, Brooklyn, NY

Designed TB transmission control systems for three areas of possible transmission; Emergency Treatment Room, Patient Waiting Room and Ward Isolation Rooms. The state-of-the-art design includes conditioned fresh air supply, HEPA filtration, UV-C disinfection and dedicated room exhaust. Iso-alert monitoring panels assure regulatory compliance.

Community Hospital of Brooklyn, Brooklyn, NY

Designed and installed a ventilation system for the Nuclear Medicine Test Room and Nuclear Chemicals Storage Room. In compliance with the N.Y.C. Department of Health Code, the ventilation system allows use of an advanced Picker machine which utilizes an aerosol DTPA radioactive tracer.