University utilizes ductless containment hood for bone DNA extraction

Direkli Mağarası'ndaki kazılarda ortaya çıkan kemikler, Anadolu insanının gen yapısına ilişkin ipuçları verecek. (İsmail Hakkı Demir - Anadolu Ajansı)

Traditional DNA specimens gathered at crime and trauma scenes include hair, blood, saliva, and other bodily fluids. In most cases these are excellent sources for identifying human remains.

Unfortunately, if a body is severely decomposed, exposed to extreme environmental conditions, or only skeletal remains are found, it makes recovering DNA that much more difficult. In these extreme cases, forensic scientists are turning to bones.

In an August 2004 article in the Journal of Forensic Sciences entitled “A Simple and Efficient Method for Extraction DNA from Old and Burned Bone”, the authors noted that “compared with the DNA in soft tissue samples, DNA in bone samples is more resistant to the environment’s chemical and physical erosion because of the protection afforded to it by the bone itself.”

University trains students in the art of DNA extraction

sam-houston-state-universityStudents in the Forensic Science Department at Sam Houston State University (SHSU) are learning how to extract DNA from bone specimens gathered from the University’s body farm.

Dr. Sheree Hughes-Stamm, Clinical Assistant Professor of Forensic Science at SHSU, explains the types of DNA one can extract from bone.

“You will be able to extract both nuclear and mitochondrial DNA from bone. However, sometimes the nuclear DNA is too degraded, and/or is in too small amounts to be useful. Therefore mitochondrial DNA is generally used as a last resort for identification.”

In preparation for DNA extraction, students clean the bones with ethanol and bleach. Samples are then ground and cut into powder form. This process creates respiratory hazards for faculty and students and proper engineering safety controls should be implemented to avoid breathing chemical vapors and biological particulate.

The following tables outline both permissible and recommended exposure limits to these hazards as well as known side effects.

Ethyl Alcohol (Ethanol)
Exposure Limits Symptoms
1,000 PPM TWA 

1,000 PPM TWA

·         Irritation to eyes, skin, nose
·         Headache
·         Drowsiness
·         Exhaustion
·         Narcosis
·         Cough
·         Liver damage
·         Anemia


Sodium Hypochlorite (Liquid Bleach)
Exposure Limits Symptoms
0.5 PPM STEL (as Chlorine)

1,000 PPM TWA

·         Irritation to eyes, skin, nose
·         Headache
·         Drowsiness
·         Exhaustion
·         Narcosis
·         Cough
·         Liver damage
·         Anemia

Ductless Containment Hood for Dust and Vapor Control

Sentry Air Systems (SAS) designs and manufactures a line of Ductless Containment Hoods that help control dust and vapor-laden air through the use of high quality filter media.

Contaminants generated within the hood’s work area are pulled via high powered fan through a series of filters before cleansed air is recirculated back into the room. This process of filtering and recycling the air saves both money and space as dedicated ductwork is not required.


Sentry Air at SHSU


Sentry Air Model 330 Ductless Containment Hood shown on the right at SHSU Forensic Lab

As an alumnus of SHSU, Sentry Air Systems Sales Manager, Omar Ilsever, made an in-kind donation to the Forensic Science Department; which included one of our Model 330 Ductless Containment Hoods [SS-330-DCH].

The hood came equipped with HEPA and Carbon filtration to aide in the capture of both bone particulate and chemical vapor.

Now, students and faculty are able to conduct DNA extraction of bone samples within a confined space. This not only helps in reducing cross contamination in the lab, it also helps in protecting their breathing zone from respiratory hazards.


As shown above, SHSU Masters student Michelle Harrel grinds a sample of bone inside the 30” wide Ductless Containment Hood. Vinyl strip curtains attach along the access area of the hood to increase dust containment.


Another angle of the lab shows the fan/filter unit affixed to the top of the hood. Additionally, a fluorescent light is attached for greater visibility within the hood.

Sentry Air Systems is proud to have supplied our Ductless Containment Hoods to laboratories, government agencies, police stations, and universities across North America. It is our continued mission to provide simple solutions for cleaner air and to educate others on the many respiratory hazards found in the workplace.

Contact Us

For more information about chemical vapor and particulate control in a lab setting, contact Sentry Air Systems at 800.799.4609, email, visit our website or fill out the feedback form below.


Fume and dust collection during firearm coating and refinishing

badge_blue-01Refinishing and applying coatings to firearms is very detailed and can at times be cumbersome.

With several small and large parts, it is important that each step of the process be done accurately in order for the finished product to be blemish free.

The process requires several steps and each step creates its own respiratory risk to workers. Whether its chemical odors, dust particulate, or aerosol spray particles, workers should utilize engineering safety controls to help protect them from overexposure.


Cleaning the parts of a firearm is a critical first step when preparing to apply a coating. A deep, thorough clean is required in order to avoid blemishes and fingerprints on the final product.

Many coating manufacturers recommend soaking the parts in a non-water based degreaser like acetone or other similar cleaning agent.

The soaking process can expose operators to heavy chemical odors which can lead to short term side effects like headaches, nausea, and drowsiness.

In order to better contain these chemical odors, it is recommended that the soaking process be conducted within a well-ventilated area or filtered enclosure.

Sentry Air Systems line of Ductless Fume Hoods are often used for such applications.

These hoods utilize a high-powered fan and activated carbon filtration to adsorb harmful chemical molecules generated within the hood.

In the picture below, we tested one of our most popular Ductless Fume Hoods [SS-340-DCH] for an ultra-sonic cleaner application to study organic vapor containment of glycol ether, specifically Ethylene Glycol Monobutyl Ether.

DSC_5020This test is very similar to other parts cleaning applications like the one required in firearm parts preparation. (Test results posted on our website)

If you decide to use acetone as your degreaser, you may want to consider pairing your ductless fume hood with our acetone gas sensor.

ss-gs-ace1ss-gs-ace12The acetone gas sensor is a device used to detect gas concentrations near the surface of the filter outlet.

It is factory calibrated based on current OSHA and NIOSH exposure limits (in PPM) for acetone.

If the sensor detects concentrations above a certain level, the alarm will sound to alert the operator.

This is a great tool for applications that solely use acetone and want to better protect operators from over exposure.


Once the parts are cleaned, the surfaces must be prepped via abrasive blasting to allow the spray coatings to better “stick”.

Usually this is done by evenly applying aluminum oxide or garnet sand grit through a pressurized nozzle.

This process can generate heavy amounts of fine dust and sand particulate that is easily inhaled. To avoid inhalation, this work can be conducted on a downdraft bench to will help contain and capture the excess dust.

Sentry Air offers a portable downdraft bench solution with a “doghouse” enclosure that is the perfect size for small parts cleaning and blasting. Our “sit/stand” version, shown below, comes in two heights with optional clear or metal surround. The perforated work surface allows dust to fall into the HEPA filtration chamber below.


Model 435 Downdraft Bench – Sit with Clear Doghouse

Model 435 Downdraft Bench – Stand with Metal Doghouse

Model 435 Downdraft Bench – Stand with Metal Doghouse


Once all of the preparation is complete, the next step is to apply several spray paint coatings to each part. Manufacturers of the spray coatings recommend that this be done in a well-ventilated booth and to follow the safety recommendations outlined in the product’s Safety Data Sheet.

Sentry Air Systems standard line of Ductless Spray Hoods come in widths of 30”, 40”, 50” and 60”.

A highly-effective fan/filter housing mounts atop the hood and pulls hazardous aerosol overspray into the filter chamber before exhausting cleansed air back into the room.

This results in protecting the operators breathing zone as well as preventing unwanted spray particulate and odors from entering the general work area.

A spray pre-filter rack is installed within the interior of the hood to capture larger particulate, thus extending the life of the main filters within the fan/filter unit.

Standard features include a Model 300 Mounted Sentry (fan/filter unit), clear anti-static vinyl strip curtains, and a variable speed controller.

Available accessories include a magnehelic gauge, hour counter, velometer, and spill tray.

In 2009, Sentry Air commissioned a study on the effectiveness of our Ductless Spray Hoods. The study found that under normal spray operations, our Ductless Spray Hoods effectively contained aerosol particulate and did not exceed the recommended 50% of the Lower Explosive Limit (mixture of air and VOCs). The full report is on our website.

Standard 30” W Ductless Spray Hood

Standard 30” W Ductless Spray Hood

Standard 60” W Ductless Spray Hood

Standard 60” W Ductless Spray Hood

If your spray application has unique requirements, Sentry Air Systems is able to make several customizations to our hoods. Some examples include: construction material, dimensions, cutouts, multi-hinged lid, and blower size.

Custom spray hoods


70” Wide Ductless Spray Hood w/ Double Hinged Lid


50″ Wide Clear Ductless Spray Hood


70″ Wide Dual High Flow Ductless Spray Hood


50″ Wide Dual High Flow Ductless Spray Hood

Contact Sentry Air

For more information about our dust and odor containment solutions, give our applications specialists a call at 800.799.4609, email, visit our website or fill out the feedback form below.