Rome, 29 April – Nei research laboratories There are many professional figures, and/or within a specific training course, who are called upon to handle chemical agents that represent a health risk in the absence of adequate prevention practices and strategies.
And the health effects that can occur following exposure events “are the most diverse, strongly conditioned by the type of chemical agent with which one comes into contact and the exposure conditions that occur; the use of substances and mixtures in this particular working context brings the operator into contact with commonly reduced volumes of substances with different dangers, which are often used in mixtures, thus creating multiple exposures to chemical agents but at low doses”.
The second edition of a booklet, published by the Department of Medicine, Epidemiology, Occupational and Environmental Hygiene (Dimeila) of Inail, entitled “Chemical Risk. Information manual for the protection of the health of research laboratory personnel”.
The document aims to provide laboratory personnel with “a quick and easy-to-consult guide to identify the chemical risk and adopt the right good safe working practices”.
Precisely to promote information on safety in research laboratories, we will focus on some today good practices presented in the document (in the first presentation article we have already illustrated the “general principles and measures to be adopted”).
In presenting the document we focus on the following topics:
The safety of research laboratory personnel: the use of hoods
The document, which does not replace knowledge of Legislative Decree 81/2008, nor the training obligation for workers and which is edited by Lidia Caporossi, Mariangela De Rosa and Bruno Papaleo, focuses first of all on the use of hoods.
We remind you, in this regard, that, when the nature of the activity does not allow the replacement of the dangerous substance to which one is exposed, among the organizational and collective protection measures at the source of the risk there is also the use of hoods to minimize life and exposure to chemicals.
These are thegeneral principles to be adopted when using hoods”, presented in the Inail document:
- “Before starting activities, make sure the hood is in operation and check its correct functioning.
- Avoid creating air currents near an operating hood (opening doors or windows, frequent transit of people).
- Fume hoods are to be considered areas of potential danger: even extremely flammable, explosive and toxic atmospheres can develop inside them. For this reason the hood must be used correctly and always kept in perfect working order.
- Periodically replace the ventilation filters of the hoods, depending on the type of contamination and the hours of use. In any case, in the absence of more specific indications, plan to replace them at least every 9 – 12 months, regardless of the use of the hood.
- Keep the front lowered to a maximum opening of 40 cm while working; do not get inside the hood for any reason (e.g. with your head).
- The working area and all the material must be kept as much as possible towards the bottom of the hood, without having to raise the mobile front more.
- Keep only the material strictly necessary for the activity under the hood, trying not to obstruct the passage of air along the hood surface.
- Do not use the hood as a means of disposing of reagents by forced evaporation.
- When the hood is not in use, turn off the extraction and lower the front.
- When electrical equipment is used inside the hood, it must have an “electrical safety system”.
- Record the ordinary and extraordinary maintenance operations carried out on the hood in a special register”.
The safety of research laboratory personnel: gas cylinders
Another source of risks is connected to the possible use of pressurized gas cylinders.
Again from the document we take the “general principles to be adopted when using pressurized gas cylinders”:
- “It is advisable to always use particular precautions in all activities involving the use, transport and storage of containers containing compressed, liquefied and dissolved gases under pressure, even when the gas contained is an “inert” gas.
- A gas container must be put into use only if its contents and/or the associated risk are clearly identifiable, as follows:
- coloring of the ogive, according to the color codified by law;
- commercial name of the gas marked on the nose in full letters or abbreviated if it is very long;
- indelible writing, self-adhesive labels, decals placed on the body of the container or identification tag attached to the safety valve and/or the protective cap.
- In laboratories, the use of compressed, liquefied and dissolved gas cylinders under pressure is usually prohibited, except for particular needs determined by research activities.
- In the latter case, it is permitted to keep small cylinders only for the time strictly necessary, provided that:
- it is a non-flammable/non-oxidising and non-toxic gas, chemically stable (inert);
- the containers are correctly anchored to the wall near the work area;
- at the end of the working day, except for particular needs, to be assessed from time to time, the cylinders are placed back in the external storage”.
It should be noted that, in general, the color of the cylinder nose “does not so much identify the gas as the main risk associated with the gas”.
In any case, the document contains two tables, one (Table 2) with the main colors of the cylinder noses in relation to the type of danger and one (Table 3) with the colors of the noses in relation to the type of gas.
Let’s take Table 2 from the document:
Other safety precautions when using pressurized gas cylinders
We conclude by taking some from the document precautions relating to the use of cylinders:
– “Before using a container it is necessary to secure it to the wall, only in this case can the protective cap be removed.
– Containers must never be heated above 50°C and never be artificially cooled to very low temperatures.
– Gas containers must only be handled by authorized personnel.
– Cylinder valves must always be kept closed, except when in use. The opening of the valves of the containers must occur gradually and slowly.
– It is preferable to avoid the use of reducers, pressure gauges or hoses, but if it is necessary to use them they must be compliant and calibrated to withstand a pressure at least 20% higher than the maximum pressure of the cylinder.
– It is advisable to always leave a slight positive pressure inside the cylinder before returning an empty container.
– However, in the event of an inert gas leak (e.g. nitrogen, helium), it is good practice to leave the laboratory and re-enter only after having ventilated.
– All containers must be equipped with special valve protection caps, which must always remain screwed on or with other suitable protection.
– The cylinders must be handled with the utmost caution, avoiding impacts and always using appropriate means of transport.
– The rooms for storing cylinders containing flammable gases must be equipped with “safety electrical systems”, fire prevention systems and protection against electrical discharges.
– It is forbidden to store incompatible gases (e.g. fuels and oxidizers) in the same warehouse.
– The premises must be:
– marked with the name of the gas placed in storage. If different but compatible gases are present in the same warehouse, the containers must be grouped according to the type of gas contained;
– arranged to ensure that the containers are kept in a vertical position and fixed to the walls with chains or other suitable means, to avoid overturning;
– equipped with an adequate ventilation system, dry, fresh, well ventilated and free of heat sources.
– In the premises there must be:
– keep empty containers separate from full ones;
– put up signs containing indications of the prohibitions, the means of personal protection to be used, the safety regulations and the emergency interventions to be adopted in the event of an accident;
– adequate ventilation systems are present or, if not possible, automatic control and signaling systems when dangerous concentrations of gases in the air are reached. If this is not technically possible, periodic measurements should be conducted.
In conclusion, we refer you to reading the document in its entirety which contains much more information on:
- classification and labelling
- storage and handling
- personal protective equipment
- first aid management
- incompatible chemicals
- signage
Tiziano Menduto
Download the document from which the article is taken:
Inail, Department of medicine, epidemiology, occupational and environmental hygiene, “Chemical Risk. Information manual for the protection of the health of research laboratory personnel”, second edition edited by Lidia Caporossi, Mariangela De Rosa and Bruno Papaleo, second edition 2023, Research Series (PDF format, 1.32 MB).
Go to the area reserved for subscribers dedicated to “Chemical risk and the protection of the health of research laboratory personnel”.
