Police were investigating a suspected double suicide today after the bodies of two women were found in a flat.
Emergency services were called to a flat in Norman Court, Lower Richmond Road, Putney, shortly before 11am.
They found the bodies of two women in a second floor flat at the red brick modern three-storey block.
Firefighters wearing breathing apparatus were brought in over fears of a chemical spill and residents asked to stay in their homes.
A Metropolitan Police spokesman said the deaths were not being treated as suspicious "at this stage" and borough detectives were responsible for the inquiry.
Lower Richmond Road was cordoned off causing lengthy traffic jams in the busy south west London neighbourhood.
The spokesman added: "Police were called at 10.42am today to a second floor flat in Norman Court, Lower Richmond Road, SW15.
"The bodies of two women were found at the scene. No arrests have been made and inquiries continue.
"Police, London Fire Brigade and London Ambulance Service remain at the scene."
One neighbour, who overlooks the property, said he was told the women were young and had taped the windows of their flat closed.
The man, who asked not to be named, said: "We have been told two women taped up their windows and committed suicide.
"I am sure that is what happened, they committed suicide. It seemed firefighters feared there was some kind of toxic substance.
"The block is L-shaped and it is a flat on Pentlow Street. It is not on the main street. The block is mainly pensioners, but the women were apparently young."
Last week a young woman killed herself in a car with a stranger after making a suicide pact online.
The bodies of Joanne Lee, 34, of Great Notley, Essex, and Stephen Lumb, 35, of Sowerby Bridge, West Yorkshire, were found in a car in Braintree, Essex.
The pair killed themselves by releasing toxic hydrogen sulphide inside the vehicle and left posters warning anyone who found them to be careful.
Investigators feared the tragedy could be the first "chemical suicide" of its kind in the Britain.
Firefighters said similar tragedies have been seen in Japan and the United States in recent years.
A member of staff at a shop close to the flat said several neighbours of the women had spoken to him since the incident.
He said: "Apparently they called police this morning saying they were committing suicide using gas or some kind of chemical.
"The police came here and found the flat sealed with tape, including the windows, and started to investigate.
"One neighbour said one of the girls was 26 years old and someone else said they were a couple.
"All these people are here because they were using chemicals and they wanted to be sure in this residential area that no-one suffered any harm."