<xs:simpleType name="MassPerMassUom">
  <xs:restriction base="eml:UomEnum">
    <xs:enumeration value="%">
      <xs:annotation>
        <xs:documentation>percent</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="%[mass]">
      <xs:annotation>
        <xs:documentation>percent [mass basis]</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="Euc">
      <xs:annotation>
        <xs:documentation>euclid</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="g/kg">
      <xs:annotation>
        <xs:documentation>gram per kilogram</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="g/t">
      <xs:annotation>
        <xs:documentation>gram per tonne</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="kg/kg">
      <xs:annotation>
        <xs:documentation>kilogram per kilogram</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="kg/sack[94lbm]">
      <xs:annotation>
        <xs:documentation>kilogram per 94-pound-sack</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="kg/t">
      <xs:annotation>
        <xs:documentation>kilogram per tonne</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="mg/g">
      <xs:annotation>
        <xs:documentation>milligram per gram</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="mg/kg">
      <xs:annotation>
        <xs:documentation>milligram per kilogram</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="ng/g">
      <xs:annotation>
        <xs:documentation>nanogram per gram</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="ng/mg">
      <xs:annotation>
        <xs:documentation>nanogram per milligram</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="ppk">
      <xs:annotation>
        <xs:documentation>part per thousand</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="ppm">
      <xs:annotation>
        <xs:documentation>part per million</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="ppm[mass]">
      <xs:annotation>
        <xs:documentation>part per million [mass basis]</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="ug/g">
      <xs:annotation>
        <xs:documentation>microgram per gram</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
    <xs:enumeration value="ug/mg">
      <xs:annotation>
        <xs:documentation>microgram per milligram</xs:documentation>
      </xs:annotation>
    </xs:enumeration>
  </xs:restriction>
</xs:simpleType>