BURNABY, B.C. - Most of the mess made by a pipeline rupture that sprayed crude oil around a suburban B.C. neighbourhood has been cleaned up, but things are still murky when it comes to laying blame.

A representative of Kinder Morgan, the company that owns the pipeline, says 80 per cent of the oil has been cleaned up since last Tuesday's spill and all but seven of the 40 families who left their homes have returned. But it's still not clear whether the maps supplied by Kinder Morgan were inaccurate or the contractor doing the sewer upgrade work made a mistake.

The contracting company has never commented publicly about the accident.

About 234,000 litres of oil spewed like a geyser for nearly half an hour when a backhoe pierced the pipeline.

"I believe (the map) was accurate," Paul Huddleston said Monday at a news briefing.

The Transportation Safety Board, which was not represented at the briefing, is interviewing people and gathering information and data about the incident.

Senior investigator Art Nordholm said after the information is assembled and pieced together, "then we (will) start analyzing the data to find safety deficiencies and cause."

"Hopefully we might learn something that we can share with municipalities or cities . . . to prevent a recurrence," said Nordholm, who expects the probe to take several months.

"We're working hand in hand with (the National Energy Board). They're looking at it from their viewpoint for regulatory infractions and we're looking at it from the safety part. We have independent investigations but we share the facts."

Representatives for Fraser Health went door-to-door in the neighbourhood that was initially evacuated, checking to see if residents were experiencing any symptoms.

Fourteen people reported suffering from nausea, throat irritations and headaches. Health officials are expected to check back with the residents in a few days.

Huddleston said counselling was available to people in the area, including members of the First Nations groups.

The oil from the spill spread for several days after the rupture to nearby parks and beaches along the north shore.

Lance Sundquist with the B.C. Ministry of the Environment said the oil sheen could be seen as far as Vancouver's Canada Place and Deep Cove, in the District of North Vancouver.

One park in the area was closed for a few days because of the oil but reopened after it had been cleaned.

Sundquist said the oil didn't pose an impact or risk to people but should be avoided.

"It's very, very thin so it's non-recoverable," he said. "There's not the ability to be able to recover it...a couple of hours in a heated condition and it's gone."

Focus Wildlife, an emergency response group, has recovered 15 birds affected by the oil and they are being rehabilitated.