Okla. Stat. tit. 36, § 36-4218

No policy of industrial insurance shall contain any of the

following provisions:

1. A provision by which the insurer may deny liability under

the policy for the reason that the insured has previously obtained

other insurance from the same insurer.

2. A provision giving the insurer the right to declare the

policy void because the insured has had any disease or ailment,

whether specified or not, or because the insured has received

institutional, hospital, medical or surgical treatment or attention,

except a provision which gives the insurer the right to declare the

policy void if the insured has, within two (2) years prior to the

issuance of the policy, received institutional, hospital, medical or

surgical treatment or attention and if the insured or claimant under

the policy fails to show that the condition occasioning such

treatment or attention was not of a serious nature or was not

material to the risk.

3. A provision giving the insurer the right to declare the

policy void because the insured has been rejected for insurance,

unless such right be conditioned upon a showing by the insurer that

knowledge of such rejection would have led to a refusal by the

insurer to make such contract.