London firefighters waited outside an apartment fire for an Ontario Fire Marshall to arrive at the site of an apartment fire at 85 Walnut Street. (Mike Hensen/The London Free Press file photo)

London police have charged a man with arson following a fire last month at an apartment building that injured four people.

Firefighters responded to a blaze at 85 Walnut St., a building run by London and Middlesex Housing Corp., on March 12 at 3:25 a.m.

The fire started in a 14th-floor unit where an ailing woman lived with her brother, who was acting as her caretaker.

The woman was critically injured, while her brother and another resident were treated for smoke inhalation. All have since been released from hospital, police said.

A firefighter also was injured battling the blaze that caused an estimated $85,000 damage.

A 65-year-old London man is charged with arson with disregard for human life and arson causing property damage.

The 232-unit highrise west of Wharncliffe Road and Riverside Drive is a geared-to-income building for seniors.

Source: Highrise fire fuels arson charge