Safe work with biological agents of risk group 3**

In section 5.4.1 TRBA 100 “Protective measures for activities involving biological agents in laboratories”, biological agents of the Risk group (RG) 3 , which are not normally transmitted through the air, marked with two asterisks (RG 3**) . These include, for example, HIV, HBV, and HCV. According to Directive 2000/54/EC, certain protection level 3 measures can be waived for these biological agents if only these are used. But what are these measures?

TRBA 100 provides information on this, but does not indicate which measures of protection level 3 can be dispensed with, but rather specifies the additional measures required to protect employees based on the measures of protection level 2. The requirements apply to targeted and non-targeted activities with biological agents of RG 3**, if the risk assessment shows that protective measures at protection level 2 are insufficient. This includes, for example, the thermal treatment of wastewater from sinks and showers. In addition, there must be a communication system between the laboratory and the outside area, emergency lighting, and dedicated equipment (laboratory tools). A lock with a hand basin or a constant, controlled negative pressure with exhaust air filtration (HEPA) are not required at protection level 2, where biological agents of RG 3** are handled, because RG 3** organisms are not transmitted through the air.

The organizational protective measures for activities involving RG 3** biological agents are generally not as extensive as for activities involving RG 3 biological agents. For example, the internal transport of RG 3 biological agents must be carried out in a primary container located within a secondary container. Personal protective clothing in protection level 2, which involves handling RG 3** biological agents, must generally be removed in the protection level area and not in the airlock, unlike in protection level 3. Depending on the results of the risk assessment, a face mask is required as a protective measure, but not respiratory protection, as required in protection level 3.

For activities involving biological agents of RG 3** only, the risk assessment should be used to determine which additional protective measures are necessary compared to protection level 2. TRBA 100 provides guidance here.