A congressional panel probing the mishandling of dangerous pathogens at federal laboratories will try to determine if US officials sought to cover up an incident involving deadly avian flu, its Republican chairman said on Tuesday.

Representative Tim Murphy said lawmakers will also look at whether lab workers face adequate “consequences” for failing to follow rules, and consider new legislation if penalties are lacking when actions endanger the public.

“Is it lax adherence to protocol? Are people ignoring protocol? Do they have this sense of mastery because they’ve been doing it so long,” said Murphy, who chairs the House Energy and Commerce Oversight and Investigations Subcommittee.

The panel is due to hear testimony on Wednesday from several witnesses, including Dr Thomas Frieden, director of the CDC.

The CDC has been engulfed in controversy since last month when officials revealed that 84 lab workers had potentially been exposed to live anthrax bacteria at its Atlanta campus. The public health agency later disclosed the discovery of vials containing smallpox at a National Institutes of Health facility outside Washington.

“Was there a cover-up, particularly in the long delay in notifying the head of CDC? Were they hurtling through levels of bureaucracy? Was it incompetence? Or was it a cover-up?” Murphy said.