Workers are exposed to hazardous chemicals that can cause serious injury or death every day. To protect yourself and your coworkers, it is important to understand the hazards of these chemicals and how to control them. This blog post will discuss the dangers of chemical hazards and how to prevent them from harming you and your team. Stay safe out there!
Control Measures For Chemical Hazards
Once the hazards in handling and using chemicals are identified, the next stage is to put control measures in place. This includes,
- Elimination- Options that get rid of the hazard altogether.
- Substitution- Replacing a hazardous chemical with a less hazardous one wherever possible.
- Engineering Controls- Fume Hoods, local exhaust ventilation, etc.
- Administrative control- Standard Operating Procedures (SOP), caution signages, etc.
- Personal protective equipment- Lab coats, safety glasses, hand gloves, etc.
Fume Hood Usage
- Be aware of the proper methodology for working with a fume hood.
- Do not use perchloric acid in an ordinary hood. A wash-down hood must be used for handling perchloric acid.
- Keep all apparatus at least six inches inside from the sash.
- Maintain good housekeeping in the hood at all times. Clean up the hood and remove unwanted materials at the end of the work.
- Avoid making rapid movements while operating the hood. This may cause the vapors inside the hood to escape. The sash must be lowered and raised slowly.
- Do not place electrical receptacles inside the hood.
- A safety shield can be placed inside the hood as an additional precaution if there is a chance of a runaway reaction.
- Keep only materials required for immediate use inside the hood.
- Never use the fume hood as a place for storing chemical bottles or containers.
- Flammable chemicals must not be stored inside the fume hood.
- Use personal protective equipment while working with a fume hood, depending upon the type of chemical used and its hazard.
- Test the performance of the hood at least once in six months. The face velocity test measures the velocity of the air as it enters the sash.
- Do not store materials blocking the baffles. If equipment has to be placed, it must be kept on raised stands to allow free air flow below.
- For fume hoods, the exhaust fan must create a face velocity of 30 meters per minute at normal working height. Those fume hoods handling highly toxic materials require higher face velocities of 45 meters per minute.
- While operating the fume hood, ensure that the sash is placed at the safe limit mark indicated on the fume hood.
- Never put your head inside the fume hood or raise the sash above the safe limit while working.
- Wherever possible, avoid working while sitting opposite the fume hood. As flying fragments of glass would be hurled out if there is a failure of equipment and if the sash is kept open.
- Keep the sash of the fume hood closed while the fume hood is not in use.
Local Exhaust Ventilation
Local exhaust ventilation helps to remove the vapors/gases/ dust from the point of the generation before it reaches the breathing zone of the user. A local exhaust ventilation system consists of
- a hood or opening that captures the vapors/dust at the source,
- ducts that transfer the contaminant from the hood,
- fan/blower that discharges air outdoors and
- an exhaust stack from which the contaminated air is discharged outside.
Personal Protective Equipment
Irrespective of the engineering and administrative controls adopted in the laboratory, personal protective equipment must be used by all personnel working or entering the labs.
Lab coat, safety glasses/goggles, and shoes are a minimum requirement for working inside labs.
Open-toed footwear must not be used in the lab, as it will not offer protection in case of a chemical spill.
Personal protective equipment and those mentioned above must be used based on the hazards involved in the task.
While selecting personal protective equipment, the following points must be kept in mind.
- It must be appropriate to the hazards of the job done.
- It must properly fit the user and be comfortable to use.
- Regularly maintained and replaced as per the manufacturer’s recommendation.
- If reusable must be properly cleaned and disinfected.
- After use, the personal protective equipment must be stored away from the work area at a designated place to prevent contamination and damage.
All personal protective equipment must conform to relevant Indian or International Standards (European Union/American National Standards Institute). The standard number will be specified on the equipment.
Never use damaged personal protective equipment.
Hand gloves protect the skin from chemical contact. Types of hand gloves for chemical handling are nitrile, butyl, neoprene, PVC, etc.
No single glove material is resistant to all chemicals. The most appropriate glove must be selected per the recommendations the chemical manufacturer gave in the MSDS.
The same can be cross-checked by referring to details given in the literature. Details of the chemical resistance of hand gloves can also be obtained here.
The gloves, irrespective of the material used, will not remain impervious to a chemical forever.
Some chemicals will travel through or permeate gloves within a few minutes, while others may take a few days or weeks. Details of the same must be obtained from the manufacturer.
The best type of chemical protective material (e.g., neoprene, butyl rubber) can be determined by referring to MSDS.
Handling of certain chemicals requires double gloves, e.g., Hydrofluoric acid (nitrile and neoprene hand gloves to be used).
Eye protection-Safety glasses and safety goggles
- Laboratory operations involve the risk of eye injuries due to chemical contact or flying fragments in case of failure of apparatus or equipment. Safety glasses/safety goggles offer protection from the above-mentioned risks.
- Goggles can be used if there are chances of chemicals splashing during handling or from the experimental setup.
- Goggles provide a tight seal around the eyes.
- A face shield offers protection to the face from chemical splashes. Eye protection must be worn even when the face shield is used.
- Clean your glasses daily. Follow the manufacturer’s instructions.
- Avoid rough handling that can cause scratches on the lens.
- The glasses must fit properly. The frame must be as close as possible to the face and adequately supported by the bridge of the nose.
- Damaged glasses must not be used.
- Keep them in a case when they are not worn.
- Wherever possible, use a fume hood or local exhaust ventilation for protection from vapors and gases.
- If the task involved is such that the above facility cannot be used, then inhalation of toxic vapors can be prevented by using chemical cartridge respirators.
- The respirator must be selected based on the type of contaminant present in the work area.
- The cartridge must be replaced periodically as per the recommendations of the manufacturer.
- The chemical cartridge respirators must NOT be used in an oxygen-deficient atmosphere.
- Body protection Aprons/coveralls protect the body from chemical contact; the type and material selected depend upon the properties and hazards of the chemical being handled.
- In case of a chemical spill, ventilate the lab by opening the windows.
- Apart from persons cleaning up the spill, others must evacuate the room.
- The personnel carrying out the cleaning must wear proper personal protective equipment. This includes eye/face protection, hand gloves, and coveralls.
- Never assume that gases or vapors do not exist because of a lack of smell.
- Breathing vapors from spilled material must be avoided. Chemical cartridge respirators must be used for protection against fumes/vapors.
- Spill control kits can be used to neutralize or absorb the spilled chemical. Absorbent pillows can be laid around the spill to prevent the chemical from spreading.
- Reduce vapor concentrations by covering the surface of a liquid spill with absorbent or other suitable material specified in the safety data sheet.
- The absorbed chemical can be collected in polyethylene bags, labeled, and stored for disposal.
- In case of a major spill involving a flammable or toxic chemical, the building must be evacuated.
- In case of a major spill of toxic chemicals, the person doing the cleaning must wear a self-contained breathing apparatus (SCBA) and other protective equipment.
- If flammable vapors are involved, do not operate electrical switches in the vicinity.
- Try to turn off open flames where it is safe to do so.