Kensington & Chelsea Tenant Management Organisation (KCTMO) was paid £11m by the Royal Borough of Kensington and Chelsea to manage social housing in 2016.

KCTMO’s Adair Tower, also in north Kensington, had previously suffered a fire – the result of arson – and some residents suffered from smoke inhalation and had to be rehoused.

The London fire brigade issued an “enforcement notice” telling KCTMO to install “self-closing devices” on the front doors of flats in Adair Tower and the nearby Hazlewood Tower, built to the same design.

KCTMO, named this year among the top 100 not-for-profit firms to work for by the Sunday Times, has offered its “sincere and heartfelt condolences” to anyone affected by the fire. “It is too early to speculate what caused the fire and contributed to its spread,” the company added. “We will cooperate fully with all the relevant authorities in order to ascertain the cause of this tragedy.”

KCTMO contracted the £10m refurbishment of Grenfell to a private construction firm, Rydon, which in turn subcontracted some of the work, in an illustration of the rewards on offer to private firms from social housing projects.

One of the other firms in the chain of companies involved in the refurbishment appears to have removed a description of the project from its website.

Rydon landed an £8.6m contract to “upgrade” the Grenfell Tower, including adding the external cladding that is being investigated as a potential factor in the fire’s rapid spread.

It boasts a string of contracts for the NHS, local councils and the Ministry of Defence, while its maintenance division, which led the refurbishment of the Grenfell Tower, maintains 22,000 properties and has nearly £450m of contracts on its order book.

The company made a pre-tax profit of £14.3m last year on revenues of £271m and paid investors a dividend of £2m, the largest slice of which went to Rydon’s chief executive and largest shareholder, Robert Bond, 61.

The company’s highest paid director, usually the chief executive, also earned a salary of £424,000 in 2016, a pay rise from £392,000 the year before.

“We are shocked to hear of the devastating fire at Grenfell Tower and our immediate thoughts are with those that have been affected by the incident, their families, relatives and friends,” the company said.

It insisted its work “met all required building control, fire regulation and health and safety standards”.

“We will cooperate with the relevant authorities and emergency services and fully support their inquiries into the causes of this fire at the appropriate time.

“Given the ongoing nature of the incident and the tragic events overnight, it would be inappropriate for us to speculate or comment further at this stage.”

After Rydon won the contract to refurbish Grenfell, it commissioned the ventilation specialist Witt UK to work on the project, it emerged on Wednesday.

Witt UK, based in Halifax, West Yorkshire, previously had a page on its website that boasted of work by one of its subsidiaries, PSB UK, on Grenfell Tower.

A version of the page was still available in Google’s historic “cached” data, in which the company explained that ventilation systems would protect residents from smoke in the event of a fire.

A description of the project read: “The lobby smoke ventilation system has been designed to provide the existing stairwell with protection from the ingress of smoke from a fire within a dwelling by means of a mechanical extract system.”

Witt UK is owned by the German family business Witt & Sohn, run by Dr Henrik Witt, 62, and Karsten Witt, 58.

A person who answered the UK company’s telephone said it had been advised not to comment.

According to the removed page of the Witt website, it handed over the “prestigious project” to a Birmingham-based building service engineering company called JS Wright & Co.

A spokesperson for JS Wright & Co said: “We are shocked by the catastrophic fire at Grenfell Tower in London and our thoughts are with the families, relatives and friends of all those affected by this tragic incident.

“JS Wright carried out a contract with Rydon Maintenance last year to provide Grenfell Tower with improved building services.

“Rydon Maintenance was in the process of refurbishing the building for Kensington and Chelsea Tenant Management Organisation on behalf of the council.

“Like everyone else at this stage, we are unaware of the causes of this fire but we will co-operate fully with all inquiries and investigations into this incident.”

Rydon also contracted another firm, Harley Facades, to provide the cladding that is being examined as a possible factor in the blaze.

Harley’s website reveals it was paid £2.6m for the Grenfell Tower work.

Grenfell Tower has been managed by KCTMO since 1996, when it took over responsibility from the Royal Borough of Kensington and Chelsea.

KCTMO documents reveal it put its fire safety policy under review last year, ordering changes including speeding up the installation of self-closing doors, tackling hoarding and dealing with clutter in communal areas.

According to board minutes for November 2016, KCTMO admitted it needed to adopt “a more proactive approach to the installation of self-closing devices to flat entrance doors across the stock”.

The company said it would increase the frequency of fire risk assessment reviews, install fire action notices in the entrance lobbies of all blocks and undertake “further work to address the issue of storage and charging of mobility scooters within communal areas”.

The latest accounts filed by KCTMO with Companies House show that “key management personnel”, led by the chief executive, Robert Black, shared £760,000 in salaries for managing properties in the borough.