Part of Lambeth Road was closed for nearly two hours on Tuesday afternoon due to a leaking butane gas cylinder.
The incident led to the closure of Lambeth Road between Hercules Road and Albert Embankment, including Pratt Walk.
The Metropolitan Police's major incident centre at 109 Lambeth Road was at the centre of the evacuated area.
Early reports described a "chemical incident" although a "non-suspicious" gas leak was later confirmed.
For the latest local news and events direct to your inbox every Monday, you need our weekly email newsletter SE1 Direct.