The building in Perth's CBD was evacuated on Thursday after the latest incident involving the Disrupt Burrup Hub protest group.
A woman in her 40s was taken into custody but was yet to be charged, West Australian police said.
Woodside confirmed employees were mustered to safety outside the building as police and firefighters dealt with the incident.
"The safety of our people is Woodside's highest priority," a spokeswoman said.
"We respect people's right to protest safely and legally but it is unacceptable for protest action to put our people's safety at risk.
"Woodside will be referring this matter to the relevant authorities."
Disrupt Burrup Hub campaigner Kristen Morrissey was photographed holding yellow smoke flares outside the entrance to the oil and gas giant's building.
"Today, I deployed non-toxic, non-flammable 'stench gas' to shut down business as usual for Woodside and sound the alarm about the climate and cultural emergency they are enabling at the Burrup Hub," she said in a statement released by the group.
"It continues the job we started at the Woodside AGM last month, using a harmless warning to evacuate people from potential harm, in contrast to Woodside's activities at the Burrup Hub which endangers culture, climate and their own workers."
Tactical response group officers were deployed to examine and remove an item believed to be the source of the gas.
"They are being assisted by specialists from ChemCentre," WA Police said.
"The investigation into the incident is ongoing, however at this time there is not believed to be any ongoing danger to the community."
Disrupt Burrup Hub has called for industrial development on the Burrup Peninsula, about 30km west of Karratha in the Pilbara region, to be stopped, including Woodside Energy's expansion of the Pluto gas plant.
The Burrup Peninsula, known as Murujuga to traditional owners, contains the largest and oldest collection of petroglyphs in the world.
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