HOUSTON (AP) _ A jury ordered 3M Corp. and two other companies Wednesday to pay three women $12.9 million in damages for silicone breast implants that leaked.

After more than four weeks of evidence and testimony, the Harris County jury ruled that implants used by Darla Lawson, Judy McMurry and Susan Doss caused health problems from nerve damage to lupus, a skin disease.

The jury also ruled the three companies were involved in a conspiracy to avoid responsibility.

''I think it's (the award) fabulous, not only for my clients, but for all the other women who have been injured by this product,'' said John O'Quinn, attorney for the three women.

''We continue to believe that our position is correct,'' defense attorney Joe Redden said after the verdict.

Another trial to decide punitive damages will begin Thursday, O'Quinn said. The three women had implants made either by St. Paul, Minn.-based 3M or the two companies it sold its breast implant business to in 1984 - Inamed and McGhan Medical Co. Both companies arebased in Las Vegas and owned by Don McGhan.

Telephone messages left for spokesmen at 3M and Inamed were not returned. There was no listing in the Las Vegas phone directory for either a Don McGhan or McGhan Medical.

Redden said the jury seemed to ignore his presentation that showed neither the medical or scientific community could back the women's claims.

''That's what cigarette companies are still saying about lung cancer,'' O'Quinn countered.